Most current coronavirus rules will remain in place for another four weeks after the planned 21 June unlocking, government sources have told the BBC.
Senior ministers have signed off on the decision to delay the lifting of all legal restrictions on social contact.
That could mean capacity limits for sports events, pubs and cinemas will remain and nightclubs will stay closed.
Prime Minister Boris Johnson is due to confirm the delay later at a news conference.
The extension will be put to a Commons vote this month and could trigger a sizeable Conservative backbench rebellion.
Stage four of the government’s roadmap out of lockdown would see all legal limits on social contact removed.
But many scientists have called for the reopening to be delayed to enable more people to be vaccinated and receive second doses amid rising cases of the Delta variant.
A delay would also allow for more work to be done on whether vaccines are breaking, or simply weakening, the link between infections and hospitalisations.
At current vaccination rates, almost 16 million more doses would be given during the four-week extension, including around nine million second doses for those at greater risk of serious illness.
On Sunday Prime Minister Boris Johnson said a final decision on whether the reopening should be paused had not yet been taken.
All areas of Scotland are due to move to Level Zero Covid restrictions on 28 June – meaning bigger groups can gather in cafés, pubs and restaurants, although they will still have to observe social distancing.
Limits on indoor gatherings in Northern Ireland are scheduled to be relaxed on 21 June – when the current rules in Wales will also be reviewed.
‘Break clause’
Former Conservative cabinet minister Damian Green told the BBC’s Westminster Hour that he wanted to see the decision to delay reviewed as more data becomes available.
“I think if it is as long as a month then there should be a break clause after two or maybe three weeks, to say that if we can tell by then that the rise in cases is not leading to a sort of rise in the serious illness that sends people into hospital, then we can unlock earlier,” he said.
On Sunday, Foreign Secretary Dominic Raab told the BBC’s Andrew Marr Show the government “don’t want to yo-yo in and out of measures”.
He said the decision on postponing unlocking would depend on whether the link between infections and hospital admissions had been severed.
Under stage four of the roadmap, venues and events would be allowed to operate without capacity limits and the cap on guests at weddings would also be lifted.
Even if these restrictions are removed, rules on face coverings and social distancing could remain in place.
The prime minister has previously said the government must be cautious so any easing of restrictions is irreversible.
Source: BBC
