An estimated one in 30 people were infected with Covid-19 in London between December 27 and January 2, official figures show.
The figure for south-east England and eastern England is estimated to be one in 45. Nationally, one in 50 people were thought to have the virus, according to the ONS.
England’s chief medical officer Chris Whitty said Covid-19 hospitalisations across England are “rising very rapidly and, of course, we are still in the middle of winter”.
He told the Downing Street press conference that the fastest increase of the new variant is in the east of England, London and south-east, but it is “now taking off in other areas as well”.
Yvonne Doyle, medical director for Public Health England, said: “The rapid rise in cases is highly concerning and will sadly mean yet more pressure on our health services in the depths of winter.
“That is why if we can, we must stay at home, reduce contacts and do everything possible to break the spread of this virus.
“It is by no means easy, but now more than ever we must all do our part to protect the NHS and save lives.”
London Mayor Sadiq Khan said the latest lockdown was “inevitable” and the only way to tackle the “out of control” level of Covid-19 cases.
“I continue to call on the Government to make wearing masks mandatory outdoors when in queues, streets and other crowded spaces outside.
“To limit the risk of new variants spreading, we need more rigorous testing and quarantine rules put in place at our borders and airports.
“It is also crucial that greater financial support is provided to businesses, the self-employed and those self-isolating which is still woefully insufficient.
“Londoners have already made huge sacrifices, but once again I urge each and every Londoner to follow the rules. Stay at home, protect the NHS and help to save lives.”