An estimated 1.3m people born outside the UK left the country between third quarter of 2019 and the same period in 2020, a study by the Economic Statistics Centre of Excellence (ESCoE) has shown. More than 700,000 foreign citizens may have left London, according to the study, representing a potential fall in 8 percent of the city’s population last year.

Researchers concluded that non-UK citizens may have been hardest hit by the jobs crisis.

As a result of redundancies, migrants may have opted to leave the UK instead of becoming unemployed UK residents.

The authors wrote: “It seems that much of the burden of job losses during the pandemic has fallen on non-UK workers and that has manifested itself in return migration, rather than unemployment.”

Additionally, researchers found that the NHS may struggle to establish a fair distribution system for coronavirus vaccines across the country.

They also raised concerns over potential confusion over how some jobs will be filled as European migrants return to their home countries.

The news comes as London faces new coronavirus restrictions with Mayor Sadiq Khan calling on Prime Minister Boris Johnson to impose tougher measures in the capital.

Mr Khan and London Councils chair Cllr Georgia Gould said the closure of places of worship and mandatory mask-wearing could be on the cards.

On Wednesday, Mr Khan confirmed more than 10,000 Londoners have now died with Covid-19.

She added: “This is why public services across London are urging all Londoners to please stay at home except for absolutely essential shopping and exercise.

“We know how tough this is for Londoners. Today, the thoughts of London leaders are with the thousands of Londoners in hospital battling Covid and the amazing carers fighting to save lives. We owe it to them to do all we can to keep ourselves and our loved ones safe.

“This is a dark and difficult time for our city but there is light at end of the tunnel with the vaccine rollout.

“We are asking Londoners to come together one last time to stop the spread – lives really do depend on it.”