Boris Johnson is facing mounting anger from senior Conservative MPs after announcing new lockdown restrictions for Christmas which may have to remain in place for months to combat a new strain of coronavirus. The prime minister has been accused of deliberately delaying a decision to place millions of people in London and the south-east under the new tier 4 measures to avoid scrutiny from angry backbench Tory MPs. The announcement of new measures, which was made by Johnson on Saturday, has been seized upon by Labour as evidence of “gross negligence”. The government has been aware of a new strain of the disease since September but resisted pleas from scientists and doctors for further lockdown measures until six days before Christmas. Sir Charles Walker, the vice-chairman of the Tory backbench 1922 Committee, said he believed ministers knew before Friday that they would be cancelling Christmas. “I suspect the government knew they were going to cancel Christmas on Wednesday and Thursday when they were still telling the House of Commons they planned to press ahead,” he told BBC Radio 4’s The World This Weekend. “I think many colleagues find that extremely egregious. The Christmas period was passed into law by the House of Commons in a vote after a debate. “The view of most colleagues was for that to be changed, another vote would be required in the House of Commons. So I suspect a decision was delayed until we were safely away back to our constituencies.” A critic of the UK health secretary, Matt Hancock, Walker also called for ministers to resign if they were found to have been incompetent. “Surely at some stage a senior government minister has to say ‘I have offered my resignation to the prime minister’ and the prime minister has to say ‘sadly I have had to accept it’?” he said. Another backbencher told the Guardian that MPs using a WhatsApp group were “seething” at the prime minister’s last-minute decision which has left thousands of people’s plans in chaos. “This is a failure of leadership for which we may never be forgiven. Many people were blaming previous cock-ups on Dominic Cummings. Now, it is all on the PM,” the MP said. On Sunday, Hancock said additional restrictions for England announced by the prime minister on Saturday may have to remain for “the next couple of months” while a vaccine is rolled out. “What is really important is that people not only follow them [the new rules] but everybody in a tier 4 area acts as if you have the virus to stop spreading it to other people,” he told Sky News’ Sophy Ridge on Sunday programme. “We know with this new variant you can catch it more easily from a small amount of the virus being present. “All of the different measures we have in place, we need more of them to control the spread of the new variant than we did to control the spread of the old variant. That is the fundamental problem. Hancock said that keeping the new coronavirus variant under control until a vaccine had been rolled out would be “very difficult”. “The cases in the tier 4 areas have absolutely rocketed in the last few days – the last two weeks or so. We have got a long way to go to solve this,” he said. At a press conference on Sunday responding to the announcement, Sir Keir Starmer criticised Johnson’s lack of “decisive action” over the new strain which was identified by the government in September. “It was blatantly obvious last week that the prime minister’s plan for a free-for-all over Christmas was a risk too far. “And yet, rather than listening to concerns and taking them seriously the prime minister did what he always does. Dismissed the challenge, ruffled his hair and made a flippant comment,” the Labour leader said. “How could the government allow people to go on as they were, when they knew they had lost control of the virus?” “It is an act of gross negligence by a prime minister who once again has been caught behind the curve,” he added. A third of the country will no longer be allowed to form bubbles with two other households over the festive period as the prime minister acted to deal with a virulent new strain of Covid-19 that he said “may be up to 70% more transmissible than the old variant”. At a No 10 news conference on Saturday, Johnson said he was taking the actions with a “heavy heart”, but the scientific evidence had left him with no choice. The announcements prompted a rush to the London train stations and by 7pm on Saturday, there were no tickets available online from several London stations including Paddington, King’s Cross and Euston. Footage posted on social media showed large crowds at St Pancras station waiting to board trains to Leeds. The announcements came as a hammer blow to many businesses – particularly retailers hoping to pick up some pre-Christmas sales at the end of a torrid year in which they had faced repeated orders to close. Johnson’s announcement was followed by further restrictions in Scotland and Wales. Wales went into tier 4 from Saturday midnight, with the first minister, Mark Drakeford, describing the situation as “serious”. Rules had been due to be relaxed to allow people to celebrate Christmas from 23 to 28 December, but instead the relaxation will only be allowed on Christmas Day. Nicola Sturgeon announced a travel ban into Scotland from the rest of the UK, and said the toughest level of coronavirus restrictions would apply across the country for three weeks from Boxing Day. Four of the five power-sharing parties in Northern Ireland are calling for an emergency meeting of the executive to discuss the new strain of Covid-19 found in England. Government ministers from Sinn Féin, the Alliance party and the SDLP issued a joint request for an executive meeting to be held on Sunday. In a letter seen by PA news agency, the minister for justice, Naomi Long, minister for finance, Conor Murphy, and minister for infrastructure, Nichola Mallon, raised concerns about the more infectious coronavirus variant found in England. It is understood that the minister for health, Robin Swann, from the UUP, has also written to the first minister, Arlene Foster, and deputy first minister, Michelle O’Neill, calling for an urgent meeting. It remains unclear whether the DUP has agreed. Those living in England in tiers 1, 2 and 3 are still able to form a Christmas bubble, but it can only be for Christmas Day itself – not for five days as previously announced – and people cannot stay over at another household. The restrictions however do not impact on existing support bubbles created to help with care and childcare reasons. The dramatic alterations to the policy, almost a month since it was announced and less than a week before it was due to come in force, is down to the prevalence of the newly-identified VUI2020/12/01 strain of the virus. The government’s New and Emerging Respiratory Virus Threats Advisory Group (Nervtag) presented evidence that it was spreading far faster than other versions, and that the existing tier 3 restrictions were not able to drive down its spread. Dr Chaand Nagpaul, BMA council chair, said doctors were reporting being overwhelmed by a massive rise in coronavirus patients. Speaking on Sophy Ridge on Sunday, he added: “We have just published the results of a major survey of doctors’ experience over the last week – it paints a really bleak picture.