Video report by ITV News Political Correspondent Libby Wiener
Sadiq Khan has called on household visits to be banned in London after the capital was added to the national coronavirus watchlist.
The Mayor of London told the Guardian it was "bad news" the capital was added to the watchlist, but that it meant the government will now "pull their finger out and give us additional support" in terms of increased testing.
Mr Khan said the extent of coronavirus in the capital might be being masked by what he said was a 43% fall in Covid tests between mid-August and mid-September.
While no additional measures have been announced for London on Friday, Leeds is set to see stricter local restrictions amid rising cases in both cities.
The government is expected to announce that people in Leeds will be banned from meeting with other households from midnight on Friday, Leeds City Council has warned.
ITV News Correspondent Damon Green reports from Leeds:
As cases across the capital rise, London Councils said its boroughs were ready to "enforce the new restrictions and regulations if necessary".
The group called on the government to "sustain" the higher number of Covid-19 tests available "from now on".
In a statement, they said: "As London goes on the national Covid-19 watchlist, it is a stark reminder that now is time 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 measures at this stage but it is welcome that that the city’s testing capacity is boosted so that Londoners have timely access to Covid-19 tests and the government must ensure that this is sustained from now on."
The news comes as the estimated number of cases of coronavirus across England jumped 60% in one week, according to new Office for National Statistics data.
Measures announced by the Prime Minister earlier in the week are hoped to combat the surging second wave.
Swathes of people were filmed heading home at the same time on Thursday evening in London, as the government’s new 10pm curfew came into force in pubs and restaurants.