TOPSHOT - Pedestrians walk along the Thames river embankment near the Tower Bridge in central London on February 4, 2021, during the third national coronavirus lockdown. - Oxford University announced on Thursday it will launch a medical trial alternating doses of Covid-19 vaccines created by different manufacturers, the first study of its kind. (Photo by Niklas HALLE'N / AFP)

A jogger runs along the Thames river embankment near the Tower Bridge in central London on February 4, 2021, during the third national coronavirus lockdown. - Oxford University announced on Thursday it will launch a medical trial alternating doses of Covid-19 vaccines created by different manufacturers, the first study of its kind. (Photo by Niklas HALLE'N / AFP)

A man walks his dog along the Thames river embankment near the Tower Bridge in central London on February 4, 2021, during the third national coronavirus lockdown. - Oxford University announced on Thursday it will launch a medical trial alternating doses of Covid-19 vaccines created by different manufacturers, the first study of its kind. (Photo by Niklas HALLE'N / AFP)

A man excercises his dog along the Thames river embankment near the Tower Bridge in central London on February 4, 2021, during the third national coronavirus lockdown. - Oxford University announced on Thursday it will launch a medical trial alternating doses of Covid-19 vaccines created by different manufacturers, the first study of its kind. (Photo by Niklas HALLE'N / AFP)

A jogger runs along the Thames river embankment near the Tower Bridge in central London on February 4, 2021, during the third national coronavirus lockdown. - Oxford University announced on Thursday it will launch a medical trial alternating doses of Covid-19 vaccines created by different manufacturers, the first study of its kind. (Photo by Niklas HALLE'N / AFP)

A man walks along the Thames river embankment near the Tower Bridge in central London on February 4, 2021, during the third national coronavirus lockdown. - Oxford University announced on Thursday it will launch a medical trial alternating doses of Covid-19 vaccines created by different manufacturers, the first study of its kind. (Photo by Niklas HALLE'N / AFP)

Pedestrians walk along the Thames river embankment near the Tower Bridge in central London on February 4, 2021, during the third national coronavirus lockdown. - Oxford University announced on Thursday it will launch a medical trial alternating doses of Covid-19 vaccines created by different manufacturers, the first study of its kind. (Photo by Niklas HALLE'N / AFP)

Construction walkers take a break along the Thames river embankment near the Tower Bridge in central London on February 4, 2021, during the third national coronavirus lockdown. - Oxford University announced on Thursday it will launch a medical trial alternating doses of Covid-19 vaccines created by different manufacturers, the first study of its kind. (Photo by Niklas HALLE'N / AFP)

People take their daily excercise along the Thames river embankment near the Tower Bridge in central London on February 4, 2021, during the third national coronavirus lockdown. - Oxford University announced on Thursday it will launch a medical trial alternating doses of Covid-19 vaccines created by different manufacturers, the first study of its kind. (Photo by Niklas HALLE'N / AFP)

Pedestrians walk along the Thames river embankment near the Tower Bridge in central London on February 4, 2021, during the third national coronavirus lockdown. - Oxford University announced on Thursday it will launch a medical trial alternating doses of Covid-19 vaccines created by different manufacturers, the first study of its kind. (Photo by Niklas HALLE'N / AFP)

A man walks his dogs along the Thames river embankment in central London on February 4, 2021, during the third national coronavirus lockdown. - Oxford University announced on Thursday it will launch a medical trial alternating doses of Covid-19 vaccines created by different manufacturers, the first study of its kind. (Photo by Niklas HALLE'N / AFP)

Mannequins are seen piled up through the window of a closed brach of Topshop on Oxford Street in London, Monday, Feb. 1, 2021, during England's third national lockdown since the coronavirus outbreak began. Online fashion seller Asos has bought Topshop, which once boasted designs by Kate Moss and Beyonce, along with three other brands for 265 million pounds ($363 million) as rivals scoop up bargains after the collapse of Britain???s Arcadia retail group. The deal, announced Monday, puts thousands of jobs at risk because Asos acquired the Topshop, Topman, Miss Selfridge???s and HIIT brands but none of their stores. (AP Photo/Matt Dunham)

A sign on the window of a closed brach of Topshop on Oxford Street in London, Monday, Feb. 1, 2021, during England's third national lockdown since the coronavirus outbreak began. Online fashion seller Asos has bought Topshop, which once boasted designs by Kate Moss and Beyonce, along with three other brands for 265 million pounds ($363 million) as rivals scoop up bargains after the collapse of Britain???s Arcadia retail group. The deal, announced Monday, puts thousands of jobs at risk because Asos acquired the Topshop, Topman, Miss Selfridge???s and HIIT brands but none of their stores. (AP Photo/Matt Dunham)

People walk past a closed brach of Topshop next to a bus stop coronavirus information sign on Oxford Street in London, Monday, Feb. 1, 2021, during England's third national lockdown since the coronavirus outbreak began. Online fashion seller Asos has bought Topshop, which once boasted designs by Kate Moss and Beyonce, along with three other brands for 265 million pounds ($363 million) as rivals scoop up bargains after the collapse of Britain???s Arcadia retail group. The deal, announced Monday, puts thousands of jobs at risk because Asos acquired the Topshop, Topman, Miss Selfridge???s and HIIT brands but none of their stores. (AP Photo/Matt Dunham)

A woman wearing a face mask to curb the spread of coronavirus walks past a closed brach of Topshop on Oxford Street in London, Monday, Feb. 1, 2021, during England's third national lockdown since the coronavirus outbreak began. Online fashion seller Asos has bought Topshop, which once boasted designs by Kate Moss and Beyonce, along with three other brands for 265 million pounds ($363 million) as rivals scoop up bargains after the collapse of Britain???s Arcadia retail group. The deal, announced Monday, puts thousands of jobs at risk because Asos acquired the Topshop, Topman, Miss Selfridge???s and HIIT brands but none of their stores. (AP Photo/Matt Dunham)

A man wearing a face mask to curb the spread of coronavirus walks past a closed brach of Topshop where Old Quebec Street joins Oxford Street, in London, Monday, Feb. 1, 2021, during England's third national lockdown since the coronavirus outbreak began. Online fashion seller Asos has bought Topshop, which once boasted designs by Kate Moss and Beyonce, along with three other brands for 265 million pounds ($363 million) as rivals scoop up bargains after the collapse of Britain???s Arcadia retail group. The deal, announced Monday, puts thousands of jobs at risk because Asos acquired the Topshop, Topman, Miss Selfridge???s and HIIT brands but none of their stores.(AP Photo/Matt Dunham)

Mannequins seen through the window of a closed brach of Topshop on Oxford Street in London, Monday, Feb. 1, 2021, during England's third national lockdown since the coronavirus outbreak began. Online fashion seller Asos has bought Topshop, which once boasted designs by Kate Moss and Beyonce, along with three other brands for 265 million pounds ($363 million) as rivals scoop up bargains after the collapse of Britain???s Arcadia retail group. The deal, announced Monday, puts thousands of jobs at risk because Asos acquired the Topshop, Topman, Miss Selfridge???s and HIIT brands but none of their stores. (AP Photo/Matt Dunham)

Mannequins seen through the window of a closed brach of Topshop on Oxford Street in London, Monday, Feb. 1, 2021, during England's third national lockdown since the coronavirus outbreak began. Online fashion seller Asos has bought Topshop, which once boasted designs by Kate Moss and Beyonce, along with three other brands for 265 million pounds ($363 million) as rivals scoop up bargains after the collapse of Britain???s Arcadia retail group. The deal, announced Monday, puts thousands of jobs at risk because Asos acquired the Topshop, Topman, Miss Selfridge???s and HIIT brands but none of their stores. (AP Photo/Matt Dunham)

A woman wearing a face mask to curb the spread of coronavirus walks past a closed brach of Topshop and a social distancing sign where Old Quebec Street joins Oxford Street, in London, Monday, Feb. 1, 2021, during England's third national lockdown since the coronavirus outbreak beganOnline fashion seller Asos has bought Topshop, which once boasted designs by Kate Moss and Beyonce, along with three other brands for 265 million pounds ($363 million) as rivals scoop up bargains after the collapse of Britain???s Arcadia retail group. The deal, announced Monday, puts thousands of jobs at risk because Asos acquired the Topshop, Topman, Miss Selfridge???s and HIIT brands but none of their stores. (AP Photo/Matt Dunham)

A woman wearing a face mask to curb the spread of coronavirus walks past a closed brach of Topshop on Oxford Street in London, Monday, Feb. 1, 2021, during England's third national lockdown since the coronavirus outbreak began. Online fashion seller ASOS says it has bought Topshop along with three other brands for 265 million pounds ($363 million), in a deal announced Monday, that puts thousands of jobs at risk because ASOS acquired the Topshop, Topman, Miss Selfridge's and HIIT brands but none of their stores. (AP Photo/Matt Dunham)

Mark "Baz" Butcher, landlord of The White Hart of Wytham, poses for a photograph outside his pub in Oxford on January 29, 2021. - The faded sign of The Lamb & Flag swung in the wind as staff removed barrels from one of Oxford's oldest pubs, which has closed permanently during the coronavirus lockdown. As the 16th-century inn wound up its operations, Oxford landlords warned of the "devastating" impact of national lockdowns on the university city's cosy pubs. (Photo by ADRIAN DENNIS / AFP)

Mark "Baz" Butcher, landlord of The White Hart of Wytham poses for a portrait in the stables, part of his pub, in Oxford on January 29, 2021. - The faded sign of The Lamb & Flag swung in the wind as staff removed barrels from one of Oxford's oldest pubs, which has closed permanently during the coronavirus lockdown. As the 16th-century inn wound up its operations, Oxford landlords warned of the "devastating" impact of national lockdowns on the university city's cosy pubs. (Photo by ADRIAN DENNIS / AFP)

Jacqueline Paphitis, landlady of the White Horse pub , poses for a photograph behind the bar in Oxford on January 29, 2021. - The faded sign of The Lamb & Flag swung in the wind as staff removed barrels from one of Oxford's oldest pubs, which has closed permanently during the coronavirus lockdown. As the 16th-century inn wound up its operations, Oxford landlords warned of the "devastating" impact of national lockdowns on the university city's cosy pubs. (Photo by ADRIAN DENNIS / AFP)

Dave Richardson, Oxford's Campaign for Real Ale (CAMRA) spokesperson, poses fir a photograph outside the closed-down Lamb and Flag pub, in Oxford on January 29, 2021. - The faded sign of The Lamb & Flag swung in the wind as staff removed barrels from one of Oxford's oldest pubs, which has closed permanently during the coronavirus lockdown. As the 16th-century inn wound up its operations, Oxford landlords warned of the "devastating" impact of national lockdowns on the university city's cosy pubs. (Photo by ADRIAN DENNIS / AFP)

Mark "Baz" Butcher, landlord of The White Hart of Wytham poses for a portrait in the stables, part of his pub, in Oxford on January 29, 2021. - The faded sign of The Lamb & Flag swung in the wind as staff removed barrels from one of Oxford's oldest pubs, which has closed permanently during the coronavirus lockdown. As the 16th-century inn wound up its operations, Oxford landlords warned of the "devastating" impact of national lockdowns on the university city's cosy pubs. (Photo by ADRIAN DENNIS / AFP)

Paul Silcock, landlord and co-owner of The Gardeners Arms public house, poses for a photograph behind the bar, in Oxford on January 29, 2021. - The faded sign of The Lamb & Flag swung in the wind as staff removed barrels from one of Oxford's oldest pubs, which has closed permanently during the coronavirus lockdown. As the 16th-century inn wound up its operations, Oxford landlords warned of the "devastating" impact of national lockdowns on the university city's cosy pubs. (Photo by ADRIAN DENNIS / AFP)

Jacqueline Paphitis, landlady of the White Horse pub, poses for a pohtograph in Oxford on January 29, 2021. - The faded sign of The Lamb & Flag swung in the wind as staff removed barrels from one of Oxford's oldest pubs, which has closed permanently during the coronavirus lockdown. As the 16th-century inn wound up its operations, Oxford landlords warned of the "devastating" impact of national lockdowns on the university city's cosy pubs. (Photo by ADRIAN DENNIS / AFP)

A general view of the White Horse pub in Oxford on January 29, 2021. - The faded sign of The Lamb & Flag swung in the wind as staff removed barrels from one of Oxford's oldest pubs, which has closed permanently during the coronavirus lockdown. As the 16th-century inn wound up its operations, Oxford landlords warned of the "devastating" impact of national lockdowns on the university city's cosy pubs. (Photo by ADRIAN DENNIS / AFP)

Paul Silcock, landlord and co-owner of The Gardeners Arms public house, poses for a photograph in Oxford on January 29, 2021. - The faded sign of The Lamb & Flag swung in the wind as staff removed barrels from one of Oxford's oldest pubs, which has closed permanently during the coronavirus lockdown. As the 16th-century inn wound up its operations, Oxford landlords warned of the "devastating" impact of national lockdowns on the university city's cosy pubs. (Photo by ADRIAN DENNIS / AFP)

Mark "Baz" Butcher, landlord of The White Hart of Wytham poses for a portrait in the stables, part of his pub, in Oxford on January 29, 2021. - The faded sign of The Lamb & Flag swung in the wind as staff removed barrels from one of Oxford's oldest pubs, which has closed permanently during the coronavirus lockdown. As the 16th-century inn wound up its operations, Oxford landlords warned of the "devastating" impact of national lockdowns on the university city's cosy pubs. (Photo by ADRIAN DENNIS / AFP)

Mark "Baz" Butcher, landlord of The White Hart of Wytham, poses for a photograph outside his pub in Oxford on January 29, 2021. - The faded sign of The Lamb & Flag swung in the wind as staff removed barrels from one of Oxford's oldest pubs, which has closed permanently during the coronavirus lockdown. As the 16th-century inn wound up its operations, Oxford landlords warned of the "devastating" impact of national lockdowns on the university city's cosy pubs. (Photo by ADRIAN DENNIS / AFP)

Mark "Baz" Butcher, landlord of The White Hart of Wytham poses for a portrait in the stables, part of his pub, in Oxford on January 29, 2021. - The faded sign of The Lamb & Flag swung in the wind as staff removed barrels from one of Oxford's oldest pubs, which has closed permanently during the coronavirus lockdown. As the 16th-century inn wound up its operations, Oxford landlords warned of the "devastating" impact of national lockdowns on the university city's cosy pubs. (Photo by ADRIAN DENNIS / AFP)

Paul Silcock, landlord and co-owner of The Gardeners Arms public house, poses for a photograph behind the bar, in Oxford on January 29, 2021. - The faded sign of The Lamb & Flag swung in the wind as staff removed barrels from one of Oxford's oldest pubs, which has closed permanently during the coronavirus lockdown. As the 16th-century inn wound up its operations, Oxford landlords warned of the "devastating" impact of national lockdowns on the university city's cosy pubs. (Photo by ADRIAN DENNIS / AFP)

Mark "Baz" Butcher, landlord of The White Hart of Wytham, poses for a photograph outside his pub in Oxford on January 29, 2021. - The faded sign of The Lamb & Flag swung in the wind as staff removed barrels from one of Oxford's oldest pubs, which has closed permanently during the coronavirus lockdown. As the 16th-century inn wound up its operations, Oxford landlords warned of the "devastating" impact of national lockdowns on the university city's cosy pubs. (Photo by ADRIAN DENNIS / AFP)

Mark "Baz" Butcher, landlord of The White Hart of Wytham poses for a portrait in the stables, part of his pub, in Oxford on January 29, 2021. - The faded sign of The Lamb & Flag swung in the wind as staff removed barrels from one of Oxford's oldest pubs, which has closed permanently during the coronavirus lockdown. As the 16th-century inn wound up its operations, Oxford landlords warned of the "devastating" impact of national lockdowns on the university city's cosy pubs. (Photo by ADRIAN DENNIS / AFP)

Paul Silcock, landlord and co-owner of The Gardeners Arms public house poses for a photograph in Oxford on January 29, 2021. - The faded sign of The Lamb & Flag swung in the wind as staff removed barrels from one of Oxford's oldest pubs, which has closed permanently during the coronavirus lockdown. As the 16th-century inn wound up its operations, Oxford landlords warned of the "devastating" impact of national lockdowns on the university city's cosy pubs. (Photo by ADRIAN DENNIS / AFP)

Paul Silcock, landlord and co-owner of The Gardeners Arms public house poses for a photograph in Oxford on January 29, 2021. (Photo by Adrian DENNIS / AFP) (Photo by ADRIAN DENNIS / AFP) - The faded sign of The Lamb & Flag swung in the wind as staff removed barrels from one of Oxford's oldest pubs, which has closed permanently during the coronavirus lockdown. As the 16th-century inn wound up its operations, Oxford landlords warned of the "devastating" impact of national lockdowns on the university city's cosy pubs. (Photo by ADRIAN DENNIS / AFP)

Arriving passengers walk past a sign in the arrivals area at Heathrow Airport in London, Tuesday, Jan. 26, 2021, during England's third national lockdown since the coronavirus outbreak began. The British government are on Tuesday expected to discuss whether to force some travellers arriving in the UK to quarantine in hotels to try to curb the spread of coronavirus. (AP Photo/Matt Dunham)

Arriving passengers walk past a sign in the arrivals area at Heathrow Airport in London, Tuesday, Jan. 26, 2021, during England's third national lockdown since the coronavirus outbreak began. The British government are on Tuesday expected to discuss whether to force some travellers arriving in the UK to quarantine in hotels to try to curb the spread of coronavirus. (AP Photo/Matt Dunham)

People wait and arrive in the arrivals area at Heathrow Airport in London, Tuesday, Jan. 26, 2021, during England's third national lockdown since the coronavirus outbreak began. The British government are on Tuesday expected to discuss whether to force some travellers arriving in the UK to quarantine in hotels to try to curb the spread of coronavirus. (AP Photo/Matt Dunham)

People push their luggage as they leave the arrivals area at Heathrow Airport in London, Tuesday, Jan. 26, 2021, during England's third national lockdown since the coronavirus outbreak began. The British government are on Tuesday expected to discuss whether to force some travellers arriving in the UK to quarantine in hotels to try to curb the spread of coronavirus. (AP Photo/Matt Dunham)

People wait in the arrivals area at Heathrow Airport in London, Tuesday, Jan. 26, 2021, during England's third national lockdown since the coronavirus outbreak began. The British government are on Tuesday expected to discuss whether to force some travellers arriving in the UK to quarantine in hotels to try to curb the spread of coronavirus. (AP Photo/Matt Dunham)

A man pushes luggage past a welcome to London sign at Heathrow Airport in London, Tuesday, Jan. 26, 2021, during England's third national lockdown since the coronavirus outbreak began. The British government are on Tuesday expected to discuss whether to force some travellers arriving in the UK to quarantine in hotels to try to curb the spread of coronavirus. (AP Photo/Matt Dunham)

People in the arrivals area at Heathrow Airport in London, Tuesday, Jan. 26, 2021, during England's third national lockdown since the coronavirus outbreak began. The British government are on Tuesday expected to discuss whether to force some travellers arriving in the UK to quarantine in hotels to try to curb the spread of coronavirus. (AP Photo/Matt Dunham)

Pedestrians wearing masks to prevent the spread of COVID-19, walk past a department store sign on Oxford Street London, Tuesday, Jan. 26, 2021. The U.K. will soon become the fifth country in the world to record 100,000 COVID-19 deaths, after the United States, Brazil, India and Mexico ??" all of which have much larger populations than Britain's 67 million people. As of Monday, the U.K.'s official coronavirus death toll was 98,531. (AP Photo/Alastair Grant)

A man wearing a mask to prevent the spread of COVID-19, walks past a department store sign on Oxford Street London, Tuesday, Jan. 26, 2021. The U.K. will soon become the fifth country in the world to record 100,000 COVID-19 deaths, after the United States, Brazil, India and Mexico ??" all of which have much larger populations than Britain's 67 million people. As of Monday, the U.K.'s official coronavirus death toll was 98,531. (AP Photo/Alastair Grant)

A lone bus passenger sits on the top deck, wearing a mask to prevent the spread of COVID-19, in Oxford Street London, Tuesday, Jan. 26, 2021. The U.K. will soon become the fifth country in the world to record 100,000 COVID-19 deaths, after the United States, Brazil, India and Mexico ??" all of which have much larger populations than Britain's 67 million people. As of Monday, the U.K.'s official coronavirus death toll was 98,531. (AP Photo/Alastair Grant)

Pedestrians wearing masks to prevent the spread of COVID-19 walk past a department store sign on Oxford Street in London, Tuesday, Jan. 26, 2021. The U.K. will soon become the fifth country in the world to record 100,000 COVID-19 deaths, after the United States, Brazil, India and Mexico ??" all of which have much larger populations than Britain's 67 million people. As of Monday, the U.K.'s official coronavirus death toll was 98,531. (AP Photo/Alastair Grant)

Pedestrians walk past a sign advising them to keep 2 meters apart on Oxford Street in London, Tuesday, Jan. 26, 2021. The U.K. will soon become the fifth country in the world to record 100,000 COVID-19 deaths, after the United States, Brazil, India and Mexico ??" all of which have much larger populations than Britain's 67 million people. As of Monday, the U.K.'s official coronavirus death toll was 98,531. (AP Photo/Alastair Grant)

A bus approaches a digital display on a bus stop informing passengers of cleaning protocols to prevent the spread of COVID-19 in Oxford Street in London, Tuesday, Jan. 26, 2021. The U.K. will soon become the fifth country in the world to record 100,000 COVID-19 deaths, after the United States, Brazil, India and Mexico ??" all of which have much larger populations than Britain's 67 million people. As of Monday, the U.K.'s official coronavirus death toll was 98,531. (AP Photo/Alastair Grant)

A woman wearing a mask to prevent the spread of COVID-19 enters Oxford Circus tube station in London, Tuesday, Jan. 26, 2021. The U.K. will soon become the fifth country in the world to record 100,000 COVID-19 deaths, after the United States, Brazil, India and Mexico ??" all of which have much larger populations than Britain's 67 million people. As of Monday, the U.K.'s official coronavirus death toll was 98,531. (AP Photo/Alastair Grant)

A digital display on a bus stop informs passengers of cleaning protocols to prevent the spread of COVID-19 in Oxford Street in London, Tuesday, Jan. 26, 2021. The U.K. will soon become the fifth country in the world to record 100,000 COVID-19 deaths, after the United States, Brazil, India and Mexico ??" all of which have much larger populations than Britain's 67 million people. As of Monday, the U.K.'s official coronavirus death toll was 98,531. (AP Photo/Alastair Grant)

A digital display on a bus stop tells passengers that it is mandatory to wear a mask to prevent the spread of COVID-19 on public transport in London, Tuesday, Jan. 26, 2021. The U.K. will soon become the fifth country in the world to record 100,000 COVID-19 deaths, after the United States, Brazil, India and Mexico ??" all of which have much larger populations than Britain's 67 million people. As of Monday, the U.K.'s official coronavirus death toll was 98,531. (AP Photo/Alastair Grant)

Pedestrians walk past a sign advising them to keep 2 meters apart on Oxford Street in London, Tuesday, Jan. 26, 2021. The U.K. will soon become the fifth country in the world to record 100,000 COVID-19 deaths, after the United States, Brazil, India and Mexico ??" all of which have much larger populations than Britain's 67 million people. As of Monday, the U.K.'s official coronavirus death toll was 98,531. (AP Photo/Alastair Grant)

A patient is pushed on a trolley from an ambulance outside the Royal London Hospital in east London, Monday, Jan. 25, 2021, during England's third national lockdown since the coronavirus outbreak began. The U.K. is under an indefinite national lockdown to curb the spread of the new variant, with nonessential shops, gyms and hairdressers closed, most people working from home and schools largely offering remote learning. (AP Photo/Matt Dunham)

A patient arrives in an ambulance outside the Royal London Hospital in east London, Monday, Jan. 25, 2021, during England's third national lockdown since the coronavirus outbreak began. The U.K. is under an indefinite national lockdown to curb the spread of the new variant, with nonessential shops, gyms and hairdressers closed, most people working from home and schools largely offering remote learning. (AP Photo/Matt Dunham)

A patient is pushed on a trolley from an ambulance outside the Royal London Hospital in east London, Monday, Jan. 25, 2021, during England's third national lockdown since the coronavirus outbreak began. The U.K. is under an indefinite national lockdown to curb the spread of the new variant, with nonessential shops, gyms and hairdressers closed, most people working from home and schools largely offering remote learning. (AP Photo/Matt Dunham)

A patient is pushed on a trolley from an ambulance outside the Royal London Hospital in east London, Monday, Jan. 25, 2021, during England's third national lockdown since the coronavirus outbreak began. The U.K. is under an indefinite national lockdown to curb the spread of the new variant, with nonessential shops, gyms and hairdressers closed, most people working from home and schools largely offering remote learning. (AP Photo/Matt Dunham)

A person wearing a face mask to curb the spread of coronavirus walks past ambulances outside the Royal London Hospital in east London, Monday, Jan. 25, 2021, during England's third national lockdown since the coronavirus outbreak began. The U.K. is under an indefinite national lockdown to curb the spread of the new variant, with nonessential shops, gyms and hairdressers closed, most people working from home and schools largely offering remote learning. (AP Photo/Matt Dunham)

A woman wearing a face mask to curb the spread of coronavirus walks past an ambulance as a medic leaves after earlier taking a patient into the Royal London Hospital in east London, Monday, Jan. 25, 2021, during England's third national lockdown since the coronavirus outbreak began. The U.K. is under an indefinite national lockdown to curb the spread of the new variant, with nonessential shops, gyms and hairdressers closed, most people working from home and schools largely offering remote learning. (AP Photo/Matt Dunham)

A snowman stands outside Buckingam Palace during a snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice.(AP Photo/Alberto Pezzali), APTOPIX

Families play in a park during heavy snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice. (AP Photo/Kirsty Wigglesworth)

A woman walks through heavy snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice. (AP Photo/Kirsty Wigglesworth)

A bus drives through heavy snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice. (AP Photo/Kirsty Wigglesworth)

An emergency ambulance drives through heavy snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice. (AP Photo/Kirsty Wigglesworth)

A woman builds a snowman during heavy snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice. (AP Photo/Kirsty Wigglesworth)

An emergency ambulance drives through heavy snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice. (AP Photo/Kirsty Wigglesworth)

London tubes are parked as snow falls in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice. (AP Photo/Kirsty Wigglesworth)

Dog walkers makes their way through heavy snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice. (AP Photo/Kirsty Wigglesworth)

A woman shakes snow from an umbrella as she walks through heavy snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice. (AP Photo/Kirsty Wigglesworth)

Dogs play in a park during heavy snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice. (AP Photo/Kirsty Wigglesworth)

Pedestrians walk through heavy snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice. (AP Photo/Kirsty Wigglesworth)

A woman builds a snowman during heavy snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice. (AP Photo/Kirsty Wigglesworth)

Families play in a park during heavy snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice. (AP Photo/Kirsty Wigglesworth)

People make their way through heavy snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice. (AP Photo/Kirsty Wigglesworth)

Pedestrians walk in Kensington Gardens as snow falls in London, Sunday, Jan. 24, 2021. (AP Photo/Alastair Grant)

Pedestrians wearing face masks against the coronavirus pandemic walk in Kensington Gardens as snow falls in London, Sunday, Jan. 24, 2021. (AP Photo/Alastair Grant)

Pedestrians walk past Kensington Palace as snow falls in London, Sunday, Jan. 24, 2021. (AP Photo/Alastair Grant)

Pedestrians walk past Kensington Palace as snow falls in London, Sunday, Jan. 24, 2021. (AP Photo/Alastair Grant)

Pedestrians walk in Kensington Gardens next to the Round pond as snow falls in London, Sunday, Jan. 24, 2021. (AP Photo/Alastair Grant)

Pedestrians walk in Kensington Gardens as snow falls in London, Sunday, Jan. 24, 2021. (AP Photo/Alastair Grant)

Pedestrians walk in Kensington Gardens as snow falls in London, Sunday, Jan. 24, 2021. (AP Photo/Alastair Grant)

A man feeds the birds at the Round pond in Kensington Gardens as snow falls in London, Sunday, Jan. 24, 2021. (AP Photo/Alastair Grant)

A woman takes a photograph on a smart phone in Kensington Gardens as snow falls in London, Sunday, Jan. 24, 2021. (AP Photo/Alastair Grant)

A man feeds the birds at the Round pond in Kensington Gardens as snow falls in London, Sunday, Jan. 24, 2021. (AP Photo/Alastair Grant)

People take photos of Kensington Palace as snow falls snow in Kensington Gardens in London, Sunday, Jan. 24, 2021. (AP Photo/Alastair Grant)

People take a photo of a snow man built in Kensington Gardens as snow falls in London, Sunday, Jan. 24, 2021. (AP Photo/Alastair Grant)

A lion statue is covered in snow, backdropped by the top of the Elizabeth Tower, which contain the iconic bell known as Big Ben, during a snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice.(AP Photo/Alberto Pezzali)

People wear face masks as they walk on Westminster Bridge, during a snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice.(AP Photo/Alberto Pezzali)

People wear face masks as they walk on Westminster Bridge against the backdrop of the Palace of Westminster, during a snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice.(AP Photo/Alberto Pezzali)

The London eye stands during a snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice.(AP Photo/Alberto Pezzali)

A double decker bus crosses Westminster Bridge against the backdrop of the Palace of Westminster, during a snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice.(AP Photo/Alberto Pezzali)

A snowman has been made in Parliament Square during a snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice.(AP Photo/Alberto Pezzali)

People walk in Horse Guards Parade during a snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice.(AP Photo/Alberto Pezzali)

People walks in the Mall, against the backdrop of Buckingham Palace, during a snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice.(AP Photo/Alberto Pezzali)

General view of Buckingham Palace during a snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice.(AP Photo/Alberto Pezzali)

A woman wears a face mask as she walks under the trees along The Mall, during a snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice.(AP Photo/Alberto Pezzali)

A snowman stands outside Buckingam Palace during a snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice.(AP Photo/Alberto Pezzali)

A Queen's Guard stands outside Buckingam Palace during a snow fall in London, Sunday, Jan. 24, 2021. Conditions are set to become more hazardous going into the final week of January with weather warnings for snow and ice.(AP Photo/Alberto Pezzali)

Image Licensed to i-Images Picture Agency. 24/01/2021. London, United Kingdom. London Snow. Snowfall hits London during cold spell. Picture by Martyn Wheatley / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. London, United Kingdom. London Snow. Londoners enjoy the snow at Northalla Fields, Northolt, West London, as snowfall hits London during cold spell. Picture by Martyn Wheatley / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. London, United Kingdom. London Snow. Londoners enjoy the snow at Northalla Fields, Northolt, West London, as snowfall hits London during cold spell. Picture by Martyn Wheatley / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. London, United Kingdom. London Snow. Londoners enjoy the snow at Northalla Fields, Northolt, West London, as snowfall hits London during cold spell. Picture by Martyn Wheatley / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. London, United Kingdom. London Snow. Londoners enjoy the snow at Northalla Fields, Northolt, West London, as snowfall hits London during cold spell. Picture by Martyn Wheatley / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. Godstone , United Kingdom. Snow in Godstone , Surrey . Picture by Stephen Lock / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. Godstone , United Kingdom. Snow in Godstone , Surrey . Picture by Stephen Lock / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. United Kingdom. Snow in Godstone , Surrey . Picture by Stephen Lock / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. United Kingdom. Snow in Godstone , Surrey . Picture by Stephen Lock / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. Godstone , United Kingdom. Snow in Godstone , Surrey . Picture by Stephen Lock / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. Godstone,United Kingdom. Melanie Brooks and her daughter Emily (6) with the snowman they made in Godstone, Surrey, as heavy snow hit the United Kingdom. Picture by Stephen Lock / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. Godstone,United Kingdom. Melanie Brooks and her daughter Emily (6) with the snowman they made in Godstone, Surrey, as heavy snow hit the United Kingdom. Picture by Stephen Lock / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. London, United Kingdom. London Snow. Londoners enjoy the snow at Northalla Fields, Northolt, West London, as snowfall hits London during cold spell. Picture by Martyn Wheatley / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. London, United Kingdom. London Snow. Londoners enjoy the snow at Northalla Fields, Northolt, West London, as snowfall hits London during cold spell. Picture by Martyn Wheatley / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. London, United Kingdom. London Snow. Londoners enjoy the snow at Northalla Fields, Northolt, West London, as snowfall hits London during cold spell. Picture by Martyn Wheatley / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. London, United Kingdom. London Snow. Londoners enjoy the snow at Northalla Fields, Northolt, West London, as snowfall hits London during cold spell. Picture by Martyn Wheatley / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. London, United Kingdom. London Snow. Londoners enjoy the snow at Northalla Fields, Northolt, West London, as snowfall hits London during cold spell. Picture by Martyn Wheatley / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. London, United Kingdom. London Snow. Londoners enjoy the snow at Northalla Fields, Northolt, West London, as snowfall hits London during cold spell. Picture by Martyn Wheatley / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. London, United Kingdom. London Snow. Londoners enjoy the snow at Northalla Fields, Northolt, West London, as snowfall hits London during cold spell. Picture by Martyn Wheatley / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. London, United Kingdom. London Snow. Snowfall hits London during cold spell. Picture by Martyn Wheatley / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. London, United Kingdom. London Snow. Snowfall hits London during cold spell. Picture by Martyn Wheatley / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. London, United Kingdom. London Snow. Snowfall hits London during cold spell. Picture by Martyn Wheatley / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. London, United Kingdom. London Snow. Snowfall hits London during cold spell. Picture by Martyn Wheatley / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. Godstone,United Kingdom. Heavy snow in Godstone, Surrey . Picture by Stephen Lock / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. Godstone,United Kingdom. Two children jump off their giant snowballs in Godstone, Surrey, as heavy snow hits the United Kingdom. Picture by Stephen Lock / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. Godstone,United Kingdom. Snowmen in Godstone, Surrey, as heavy snow hits the United Kingdom. Picture by Stephen Lock / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. Godstone,United Kingdom. Snow in Godstone, Surrey, as heavy snow hits the United Kingdom. Picture by Stephen Lock / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. London, United Kingdom. London Snow. Snowfall hits London during cold spell. Picture by Martyn Wheatley / i-Images

Image Licensed to i-Images Picture Agency. 24/01/2021. Godstone , United Kingdom. Snow in Godstone , Surrey . Picture by Stephen Lock / i-Images