New figures show 620 new cases were confirmed in the capital in the last 24 hours – more than double the number at the start of the week.

The news was confirmed this morning by London Councils but a formal announcement is expected from Public Health England later today.

Council leaders said the decision was a ‘stark reminder’ of the need for ‘all Londoners to pull together and take action to keep themselves, their families and their communities safe, and to ensure that London’s economy is protected’.

There are no additional restrictions at this time, but leaders have called for boosted testing capacity to be sustained by the Government.

Thirty-five more Covid-19 patients have been admitted to hospital in London in the past day, bringing the total to 212. Forty of these patients are currently on ventilators.

The capital joins other areas including Bolton and Blackburn on the watch list, which is decided on by Health Secretary Matt Hancock upon advice from the chief medical officer, NHS Test and Trace, the Joint Biosecurity Centre and Public Health England.

It comes as Welsh officials confirm Cardiff and Swansea will be under new restrictions from Sunday and almost 800,000 people are expected to be put back into lockdown in Leeds.

Crowds were seen flocking onto London’s streets and the Underground last night on the first night after the introduction of the 10pm curfew.

One witness described the Tubes as ‘the busiest I’ve seen in central London for months’ as everyone ‘rolled onto the streets’ with no staggered leaving times.

London Councils said all boroughs were working with their communities, business and the police to engage, educate, explain, and if necessary enforce the new restrictions and regulations.

Deputy assistant commissioner Matt Twist, who is leading the Met’s response to the pandemic, said the ‘vast majority of Londoners’ have stuck to the rules and ‘responded positively to the unprecedented situation we are in’.