Separate households will not be allowed to meet indoors in Greater Manchester, East Lancashire, and parts of West Yorkshire from midnight, the government has announced.
Health Secretary Matt Hancock said an “increasing rate of transmission” had been identified in those areas.
“The spread is essentially thanks to households meeting and not abiding by social distancing,” he said.
He also said the same restrictions will apply to the city of Leicester.
But pubs, restaurants, and some other facilities are to be allowed to reopen from Monday in Leicester – where a local lockdown has been in place since last month – sources said.
Millions of people in Greater Manchester, Blackburn with Darwen, Burnley, Hyndburn, Pendle, Rossendale, Bradford, Calderdale, and Kirklees will be affected by the tightening of restrictions.
It is unclear whether the rules will also apply to pubs, restaurants, private gardens, and places of worship.
“We take this action with an important heart, but we will see increasing rates of COVID across Europe and are determined to try to whatever is important to stay people safe,” Mr. Hancock.
It comes nearly four weeks after restrictions were eased and people were allowed to meet indoors.
On Thursday, a further 38 people in the UK died, bringing the total number of Covid-19 associated deaths to 45,999.
And 846 cases were reported – the highest number of cases in a day for a month.
The rise in coronavirus cases
In other developments on Thursday:
- Passengers arriving within the UK from Luxembourg from Friday will need to isolate for 14 days after the country is no longer on the quarantine-free list.
- People who test positive for coronavirus or show symptoms within the UK must now self-isolate for a minimum of 10 days, instead of seven.
- The official analysis shows the UK saw some of the biggest rises in deaths rates in Europe in the months until the middle of June
Andy Burnham, the mayor of Greater Manchester – a city with a population of about 2.8m – said there had been a “marked change in the picture” with regard to the spread of Covid-19 in the area.
“We have gone from a falling rate of cases in nearly all of our boroughs last week to a rising rate in nine out of 10 affecting communities across a much wider geography,” he said. “In Rochdale, the one borough where cases have fallen, they’re still too high.”
He said all residents “young and old alike” should “protect each other” by observing the requirements, which will be reviewed weekly.
This means “the more we stick with them, the quicker they’re going to be removed”, he said.
“This may be a place which prides itself on searching for every other. We now got to be faithful that by not acting selfishly and keeping the health of others in mind in the least times.”
Jonathan Reynolds, shadow secretary for work and pensions and an MP in the Greater Manchester area, said the figures were showing an increase in infections including in Tameside where positive tests per 100,000 population have gone from 4.9 to 16.3.
BBC News correspondent Judith Moritz said the government’s announcement was “a shock” but the data had been “pointing this way for some time”.
She said residents “will find it hard to deal with” especially those with a significant Muslim population looking to celebrate Eid on Friday.
The restrictions are not as strict as those that were imposed in Leicester, she said, but Thursday’s announcement covers a much greater area.
Leicester introduced a strict local lockdown at the beginning of July because the city’s seven-day infection rate had risen to 135 cases per 100,000 people. It has since fallen and the lockdown was lifted for some suburbs of the city.