Boris Johnson has resigned himself to a delay of up to four weeks in lifting the remaining Covid restrictions.
The Prime Minister will tell the country on Monday that the latest data on the spread of the Indian or delta virus variant means it is too risky to go ahead as planned.
A four-week delay would push the reopening date back from June 21 to July 19.
The British Medical Association became the latest body to call for a delay after data released on Friday showed the ‘R’ rate at its highest since January – between 1.2 and 1.4 – with daily cases reaching 8,125, the highest number since February.
Figures published by Public Health England showed that 42,323 cases of the Indian variant have been confirmed in the UK – an increase of 240 per cent from last week.
As cases increase, Chancellor Rishi Sunak has said he is willing to accept a short delay to Step 4 of the roadmap to ending the lockdown, The Telegraph understands.
A Whitehall source pointed towards the Treasury having gone "long" on emergency coronavirus support packages in the Budget to cover the possibility of a delay to the plans.
What will happen now?
After weeks of wrangling between ministers, scientists and business leaders, government sources confirmed on Friday, June 11, that some restrictions would remain in place beyond June 21. A four-week delay is the most likely option, pushing the date back to July 19. The decision is expected to be reviewed two weeks into the extension.
June 21 poll
Why is lockdown easing be delayed?
Mr Johnson is understood to have decided a delay of up to four weeks is necessary to allow for more people to be double-jabbed before the final restrictions are eased.
Hopes for a full reopening on that date have been affected partly by the news that both the Pfizer and AstraZeneca jabs give only 33 per cent protection after one dose, compared with up to 80 per cent protection against previous variants.
The news of the delay comes as PHE estimates that the Indian or Delta strain is 60 per cent more transmissible than the Kent or alpha variant, with cases doubling every four and a half days in some parts of England.
The ‘R’ rate is also at its highest since January – between 1.2 and 1.4 – with daily cases reaching 8,125, the highest number since February.
What will happen instead?
The Cabinet’s Covid Operations committee will meet on Sunday evening to make a final decision about any easements that can go ahead before the decision is rubber-stamped by the Cabinet on Monday morning and announced by Mr Johnson later that day.
Face coverings, work from home advice and social distancing are all expected to remain, together with the "rule of six" and restrictions on numbers allowed in arenas, theatres and other venues. Nightclubs will remain closed.
One concession confirmed by the Government was that Wimbledon would be allowed to open with a capacity of 50 per cent – up from 25 per cent – when the tennis tournament begins on June 28.
What are the scientists saying?
The Scientific Advisory Group for Emergencies is understood to have warned the Government that a third wave of Covid cases could exceed the first wave peak if the June 21 reopening were to go ahead as planned.
However, NHS leaders have said that scientific modelling has been crude and unreliable at predicting the pandemic, and they warned against using it to decide whether to release restrictions on June 21.
Chris Hopson, the chief executive of NHS Providers, said trusts were "sceptical" about the fitness of models to provide useful forecasts for the pandemic.
How does this affect businesses?
The news will come as a bitter blow to businesses that had geared up to reopen in full on June 21, with many hiring and training staff, bringing others off furlough and ordering supplies in order to offer customers a normal service.
The Treasury is so far refusing to extend the business rates freeze for the hospitality and leisure sector which ends on July 1, arguing that enough support is already in place.
Kate Nicholls, chief executive of UK Hospitality, said: "The ongoing uncertainty around the roadmap is causing significant distress to hospitality businesses and operators.
"It is crucial that the Government commits to dropping the restrictions on June 21. Any delay in the roadmap would have a devastating effect on an already fragile sector."
Sarah Haywood, of the industry body UK Weddings Taskforce, said wedding businesses would "collapse" as the result of a delay because "we have reached the end of the runway".
She said more than 50,000 weddings were booked for the four weeks after June 21, as ministers had repeatedly reassured the public that restrictions would end on that date, adding: "In every single meeting with Government, they said they were on track for unrestricted reopening, and when we pressed them for a contingency plan they wouldn’t discuss it."
Government support for affected businesses remains in place until September.
What is currently allowed?
Most of the legal restrictions on meeting outdoors were dropped on May 17 after the Government pushed ahead with Step 3 of Mr Johnson’s roadmap.
People are allowed to meet indoors too, but the rule of six or two households still applies.
Indoor dining in restaurants is already permitted and customers are no longer required to purchase substantial meals with alcoholic drinks, nor to stick to a curfew.
Gyms have reopened and certain larger performances and sporting events in indoor venues have resumed.
Up to 30 people are able to attend weddings, receptions and wakes, as well as funerals.
When is the next lockdown announcement?
The Cabinet’s Covid Operations committee will meet on Sunday evening to make a final decision about any easements that can go ahead.
The decision will be rubber-stamped by the Cabinet on Monday morning and announced by Mr Johnson later that day.
The decision is expected to be reviewed two weeks into the extension.
What is permitted in the other UK nations?
In Wales, from June 7 groups of up to 30 people were allowed meet outdoors, including in private gardens, while up to three households can meet indoors.
The Welsh government is yet to give a date for the reopening of larger venues providing live performances or for events such as outdoor music festivals.
Plans to ease lockdown restrictions in much of Scotland have been paused, but restrictions were reduced in Glasgow, which had been kept in Level 3 restrictions due to a spike in cases.
Restaurants, cafes, bars and other hospitality venues in Northern Ireland can operate indoors, with six people allowed to sit together from unlimited households with table service only.