Boris Johnson is expected to tell the country today that it is too risky to proceed with lifting Covid restrictions on June 21.
On Sunday night the Prime Minister was finalising his plan to push back the reopening in England by up to four weeks owing to a surge in cases of the Indian variant.
A four-week delay could now push back the reopening date to July 19.
Rules ordering the wearing of face masks, limiting groups to six people indoors and 30 outdoors, and keeping nightclubs shut are set to remain in place.
The cap on weddings being attended by only 30 people is expected to be relaxed, but the exact details of what new rules would replace it were still being debated in Government on Sunday night.
The Prime Minister has not ruled out further future delays raising fears of lockdown stretching into August.
Here is everything we know.
Why is there a delay?
The British Medical Association became the latest body to call for a delay after data released on Friday, June 11, 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 (PHE) showed that 42,323 cases of the Indian variant had been confirmed in the UK – an increase of 240 per cent from the week before.
PHE estimates that the 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.
Where is the Indian variant in the UK?
Military personnel and extra testing have been deployed to stop the spread of the Indian variant.
However, hospitals in Covid hotspots are seeing a "significantly" lower death rate among people admitted for treatment and are coping with current levels of infection, the head of NHS Providers said on June 9.
Hopes for a full reopening on June 21 have also 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.
Almost 78 per cent of UK adults have had one jab, but only around 55 per cent have had two.
Downing Street’s argument for the extension is that it buys the country more time to both monitor the delta variant and, crucially, deliver millions more doses of the vaccine.
Is the UK on track to hit vaccination targets?
Step-by-step unlocking: what happens when?
The roadmap is underpinned by four key tests that are linked to data, which act like a checklist that must be met before moving on to the next step of reopening.
The tests determine whether the vaccine rollout is going as planned; vaccines are effective in bringing down deaths and hospitalisations; case numbers are not rising so fast that the NHS risks being overwhelmed; and new variants do not create unforeseen risks.
Below are the changes of the roadmap since May 17.
Roadmap – May 17
Since May 17, groups of up to six people and two households have been able to meet indoors.
Hugging is allowed between close family and friends, who can choose whether or not to socially distance. However, people are being "urged to remain cautious", and wider social distancing rules remain for adult social care, medical, retail, hospitality and business settings.
Pubs and restaurants can open indoors and venues are allowed to serve food and drink, but hospitality guidance must be observed, such as individuals remaining seated. There are no requirements for guests to be socially distanced at tables.
Outdoors, people can meet in groups of up to 30 in beer gardens or when dining al fresco.
Care home visiting has been eased further, with residents able to have up to five named visitors and greater freedoms to make low-risk visits outside of the establishments.
University students can return to face-to-face teaching on campus, replacing online lectures that have been in place for months. They should get tested twice a week upon return.
Funerals are no longer be limited to 30 mourners. Instead, the capacity is determined by how many people could be accommodated in venues such as places of worship or funeral homes while maintaining social distancing.
However, the cap of 30 people remains for weddings and other types of significant events, including bar mitzvahs and christenings.
Up to 30 people can attend a support group or parent and child group. The limit does not include children under five.
Hotels and B&Bs can open, with up to six people or two households able to meet indoors.
Additionally, professional performances can now resume indoors.
Indoor sports and gym classes can also open, along with entertainment venues, including cinemas and theatres.
People took part in a gym class starting one minute past midnight amid an easing of coronavirus restrictions, at the Park Road Fusion Lifestyle Gym in London on May 17
Credit: Neil Hall/EPA-EPE
Normal outdoor events can open for up to 4,000 people or 50 per cent of the venue capacity, whichever is smaller. Similarly, normal indoor events can open for up to 1,000 people or 50 per cent capacity, again whichever is lower.
For huge outdoor seated venues, there is a special limit. Up to 10,000 attendees are allowed or 25 per cent capacity, whichever is lower. This means, for example, Wembley Stadium can open with 10,000 fans in attendance.
The ban on overseas holidays ended on May 17, in the first step to reviving foreign travel. It is no longer illegal to go abroad, meaning summer holidays overseas are now allowed, with a traffic light system for countries in use.
However, The Telegraph reported on June 7 that Matt Hancock warned Britons that summer holidays abroad are off for the "medium term" because of the need to protect domestic freedoms "at all costs".
Traffic light travel restrictions
On June 3, ministers added Portugal, including the islands of Madeira and the Azores, to the amber list after tests revealed what are believed to be previously unknown variants of Covid.
It means that anyone returning from the tourist hotspot to the UK will have to quarantine for 10 days and take at least two PCR tests.
Egypt, Sri Lanka, Costa Rica, Bahrain, Sudan, Trinidad and Tobago and Afghanistan have been added to the red list, forcing anyone returning from them to quarantine in government-approved hotels at a cost of up to £1,750 per person.
Could there be another lockdown in 2021?
The low death rate in recent weeks led Mr Johnson to state that "nothing in the data" suggests that a third national lockdown will be implemented but local lockdowns have not been ruled out.
However, Communities Secretary, Robert Jenrick, said on June 9 that there were no plans to return to last year’s regional tiered approach to coronavirus restrictions, adding that the "best way forward" is replicating the targeted action in Bolton.
He told BBC Radio 4’s Today programme: "What we want to do is provide as much support as we possibly can to a local community and to work as closely as we can with the local leaders."
The areas where the Indian variant is increasingly prevalent
On June 8, official guidance urging people in Covid hotspots to meet outside if possible and minimise travel was extended to Greater Manchester and Lancashire – the measures were already in place in Bolton, Blackburn with Darwen and other hotspot areas.
Roughly 10 per cent of the population of England is now being advised to restrict travel out of the affected areas.
Mr Johnson’s message to the nation at a Downing Street press conference on Monday evening is expected to be that sticking to the rules now is worth it to avoid a future lockdown.