Chancellor Rishi Sunak was willing to accept a short delay to Step 4 of the road map to ending the lockdown amid a rise in cases, 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.
It comes after Matt Hancock said on June 6 that the Government was "absolutely open" to delaying the June 21 unlocking.
A two-week delay until July 5 has been under discussion by scientists and civil servants, and after being queried about the delay, the Health Secretary reminded the public that the June 21 date was the earliest at which the government would take Step 4 – rather than being set in stone.
Boris Johnson has pencilled in June 21 for the final step in his roadmap out of legal restrictions, however, he will not make a firm decision about how to proceed until a week beforehand, on June 14.
The Prime Minister is facing growing pressure to push ahead with the reopening on June 21, despite the R rate rising above one again across the UK and daily Covid cases at their highest since March 22.
It comes as Tory lockdown-sceptic Sir Charles Walker warned Prime Minister Boris Johnson against delaying the earmarked end to legal coronavirus restrictions.
The vice chairman of the 1922 Committee of Conservative MPs told BBC Newsnight on March 8: "There will be a huge wave of disappointment across the country if we don’t open up on June 21.
Nearly six million people are being urged to minimise travel as of June 8, as Mr Hancock insists the “goal” remains for the country to leave lockdown together.
Military personnel and extra testing will be deployed across the whole of Manchester and Lancashire to stop the spread of the Indian variant.
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: "We don’t have any plan to return to the regional or the tiered approach that we saw last autumn.
"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."
Mr Hancock stressed that there was a “good sign” that vaccinated people appear to make up only a small proportion of people still being hospitalised with coronavirus.
His comments came as the Government confirmed that over half the adults in the UK are now double vaccinated.
Is the UK on track to hit vaccination targets?
Mr Johnson said the data was “still ambiguous” about the extent to which the vaccination roll-out would protect the population against a new surge, however, and stressed the need for caution.
Scientists advising the Government have called for the lifting of lockdown restrictions to be delayed, warning that the UK could face a third wave of the virus as a result of the Indian variant. However, an expert has advised that delaying the June 21 reopening would be a matter of weeks rather than months.
The Indian variant is now the dominant strain in Britain, having overtaken the Kent variant, Public Health England confirmed on June 3.
The Indian variant is increasing across the country
There is now a race to offer all over-50s a second coronavirus vaccine dose before the planned end of restrictions.
Nadhim Zahawi, the vaccines minister, said the Government was aiming to offer full protection to older people before the planned unlocking amid concern that the Indian variant could throw the roadmap off course.
Additionally, fully vaccinated people will still have to self-isolate for 10 days if they come into contact with someone infected with Covid after June 21, Mr Zahawi confirmed on May 25.
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 roll-out 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.
Ministers will receive papers setting out the options from scientific advisors and officials as well as the most up-to-date data before making a decision.
Sources said the decision hinged on data on the impact of the Indian variant on hospitalisations, which are largely flat but have increased marginally in some areas.
Below are the changes of the roadmap since May 17 and those expected on June 21, although delays are possible if the data takes a negative turn.
Roadmap – May 17
Since May 17, groups of up to six people and two households can meet indoors, meaning that people can now enter each other’s homes.
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 during this stage.
The rule of six and two households rule was also introduced indoors from this date. It has been lifted outdoors, meaning 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, meaning small group trips are back on the cards, with up to six people or two households able to meet indoors.
Additionally, professional performances can now resume indoors. There is no official guidance on the number of performers permitted, but this is determined based on the capacity of the venue.
Indoor sports and gym classes can also open, along with entertainment venues, including cinemas and theatres. New rules are in place for different sizes of venues.
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 Mr Hancock warned Britons that summer holidays abroad are off for the "medium term" because of the need to protect domestic freedoms "at all costs". The Health Secretary signalled that any significant expansion of the quarantine-free green list of holiday destinations has been put on hold until later in the summer because of the risk from new virus variants.
However, Downing Street declined to rule out the possibility that Boris Johnson could go on an overseas holiday this summer on the same day George Eustice, the Environment Secretary, suggested people should be taking their summer holidays in the UK.
Mr Eustice told Sky News on June 8 he would be holidaying in Cornwall this year, adding: "Our advice has been don’t travel unless it’s absolutely necessary.
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 after 4am today, June 8, will have to quarantine for 10 days and take at least two PCR tests.
Read more: What to do about your holiday to Portugal as country moves from green to amber list
Sources said ministers had decided that with just weeks to go to the lifting of the final Covid restrictions on June 21, they should “not do anything that jeopardises further unlocking at this point”.
No countries will be added to the green list, dashing frontrunner Malta’s hopes of opening its holiday market to Britons. Hopes that the Balearics or Greek islands could be added have also been scuppered.
Traffic light travel restrictions
Instead, seven countries 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.
Egypt, Sri Lanka, Costa Rica, Bahrain, Sudan, Trinidad and Tobago and Afghanistan have been added to the red list.
Roadmap – June 21
There is a week left before the Government will reveal whether the fourth and final stage of Mr Johnson’s reopening roadmap will go ahead as planned for England.
Mr Hancock said on June 6 that the Government is "absolutely open" to delaying the June 21 unlocking.
"We are absolutely open to doing that if that’s what needs to happen. We said in the roadmap that June 21 is the date by which we would not take Step 4 before that date and that we would look at the data," he said when questioned about the possibility of a delay.
The Telegraph understands the use of masks, social distancing and advice on working from home are unlikely to be lifted on June 21 amid concern over the Indian variant.
Delaying the return to offices is seen as one of the least economically damaging options to curb its spread. While it means a low level of commuters travelling into city centres and spending money there, Government support for affected businesses remains in place until September.
A Treasury source told The Telegraph: “Obviously working from home does have some consequences, but there’s no difference between now and two weeks’ time because the economic support will still be in place. There’s not that imperative to change the advice.”
Many businesses have also indicated that they will switch to a hybrid model under which employees work from home for part of the week in future anyway.
On June 3, Prof John Edmunds, a member of the government’s Scientific Advisory Group for Emergencies (Sage), said that keeping people working from home is “one of the biggest levers” the Government could pull, in controlling the spread of the virus.
It comes as face masks should be reintroduced in classrooms, teaching unions have demanded as of June 8 as infections rise.
A joint statement, from the National Education Union (NEU), Unison, GMB and Unite, has warned more pupils are "likely to be off self-isolating and missing out on face-to-face education" in the weeks to come.
Outdoors lessons should also be encouraged to minimise any further disruption to education, the unions have urged.
Could there be another lockdown in 2021?
The low death rate in recent weeks had 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.
But after the death toll rose to 18 on June 3, and the Government announced 5,274 new positive cases reported over the 24-hour period, questions were raised again about how to prevent further deaths and hospitalisations.
Fears are growing that lockdown laws could be replaced with a web of restrictive guidance later this month in what has been dubbed by critics a “smoke and mirrors” reopening.
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.
Roughly 10 per cent of the population of England is now being advised to restrict travel out of the affected areas.
The measures are already in place in Bolton, Blackburn with Darwen and other hotspot areas and were on June 8 credited by the Health Secretary with stemming the rise in cases.
Despite this, scientists said the variant had “radiated” into neighbouring boroughs.
The areas where the Indian variant is increasingly prevalent
Dr Mike Tildesley, a member of the Scientific Pandemic Influenza Group on Modelling (Spi-M) Government advisory panel, said the June 21 proposed reopening in England will be a "really difficult decision".
He said on June 4: "I think the question the Government needs to answer, and I can’t answer this, is if we show that cases may rise, and of course hospital admissions and deaths may rise over the coming months, what kind of rise in those the Government can cope with to allow society to reopen."
In response to the spread of the Indian variant, which has been blamed for the recent spike in cases, the government wants to vaccinate as many as one million people a day as part of a drive to save the British summer.
Mr Hancock said the package of measures in Bolton and other areas had “seen a capping out of the increase in rate without a local lockdown, thanks to the enthusiasm of people locally and of course the vaccination programme”.
He told MPs on June 8: “That is our goal. Our goal is that England moves together, and that’s what we are putting these programmes in place to do, and we are seeing them work.”
The additional measures include surge testing, contact tracing, isolation support and efforts to maximise vaccine uptake.
Read more: The hotspots for the Indian variant of Covid-19 in the UK