The prime minister is “determined” that the remaining coronavirus restrictions in England will be lifted on 19 July, Downing Street has said.
Boris Johnson confirmed on Monday that measures would remain in place until then because of the rapid spread of the Delta variant.
That would be the “terminus date” for the remaining restrictions on social contact, he said.
However some Conservative MPs are concerned they could remain for longer.
Scientists advising the government had warned of a “significant resurgence” in people needing hospital treatment for Covid-19 if stage four of easing the lockdown went ahead as planned on 21 June.
The prime minister said a four-week delay would allow more people to get vaccinated.
However, a few restrictions are being lifted on 21 June, including the limit on wedding guest numbers – although venues will still have to adhere to social distancing rules.
Hospitality, wedding and night-time entertainment businesses are among those to have criticised the delay.
Cabinet Office Minister Michael Gove said he shared the prime minister’s confidence about the 19 July end date.
“One can never predict the future with perfect confidence,” he told BBC Breakfast.
“But insofar as we can be confident about anything in this complex world, we can be confident that the increased level of vaccination that we will have by 19 July should allow us to further relax restrictions.”
The confidence among ministers that all remaining restrictions will lift on 19 July is understandable given the extent of the vaccine rollout.
But behind the scenes, the one fear is what to do if cases are still rising at that point.
Infections are currently climbing sharply and modellers believe this could realistically translate into around 1,000 hospital admissions a day later in the summer.
That is equivalent to what the NHS would face for all types of respiratory illness in the middle of a bad winter.
The hope is that in a couple of weeks infection levels will have started to flatten, and maybe even fall, as the virus hits the wall of immunity built up by the vaccination programme.
But there are no guarantees of that.
Knowing the peak of this wave is still to come will make the final decision harder if hospitalisations climb as expected.
But the fact remains Covid is always going to present a risk. Exactly how much is hard to quantify at this stage, although it will of course be much much lower than it was before.
In the end it will come down to balancing that extra risk against the need to get back our old way of life and reducing the harms caused by our response to Covid.
On Monday, Health Secretary Matt Hancock said extra testing facilities and access to vaccines would be rolled out in more areas of the country, while vaccinations would be opened up on Tuesday in England to people aged 23 and 24.
The delay means limits remain on how many people can meet, with groups of up to 30 allowed to meet outdoors and up to six people or two households allowed indoors.
However, 15 coronavirus pilot events will continue as planned, including some upcoming Euro 2020 games, Wimbledon and arts and music performances. Attendees will have to show proof of vaccination or a recent negative test.
What is changing from 21 June?
The number of guests at weddings and wakes will no longer be limited to 30
But venues will have to adhere to social distancing and hosts will have to do a risk assessment
Table service will be required – with six people per table – and no indoor dance floors allowed
Care home residents will no-longer have to isolate for 14 days after returning from visits outside. Exceptions will include high-risk trips such as overnight hospital stays
Capacity limits will continue at other venues and nightclubs will stay closed.
Advice to work from home where possible will remain in place.
The extension of restrictions will be put to a Commons vote, which could trigger a sizeable Conservative backbench rebellion, with a debate expected on Wednesday
Mr Johnson said two-thirds of adults would have been offered two coronavirus jabs by 19 July, including all vulnerable groups.
The gap between doses for over-40s in England will be reduced from 12 to eight weeks.
And the target to offer all adults a first dose will be brought forward to 19 July.
New analysis by Public Health England showed two doses of either the Pfizer or AstraZeneca vaccine were highly effective at preventing hospital admissions from the Delta variant.
PHE said the effectiveness was comparable to against the Alpha variant which was previously dominant in the UK.
The Night Time Industries Association said the delay to the roadmap was a “devastating blow” that would “drive down confidence in the sector to a new low”, forcing more workers to leave the industry.
Julian Bird, chief executive of the Society of London Theatre and UK Theatre, said thousands of jobs were “hanging in the balance”, with venues no longer able to increase their capacity as planned.
Many pubs and restaurants are also trading at a loss because of social distancing measures.
Industry trade body UKHospitality called for additional financial support for affected businesses, saying the delay would cost the sector around £3bn in sales.
The government has said it will not extend the furlough scheme or other financial support further, despite the delay to the unlocking roadmap.
Downing Street said local authorities have £1bn of unspent money to support businesses, which could be used to pay business rates or contribute to furlough payments.
Under the furlough scheme, the government covers up to 80% of an employee’s salary for the hours they cannot work because of the pandemic.
The scheme is due to run until the end of September but employers will have to help cover the cost from July.