Tory MPs on Wednesday night likened the Government’s decision to delay the final lockdown unlocking to the actions of a “communist party”, as 49 voted against the four-week extension.

In what is believed to be the second largest Tory rebellion of the pandemic, Boris Johnson was accused in Parliament of “shifting the goalposts” again and warned the delay was a “moral threat” to the Conservative Party. 

Others urged the Prime Minister not to squander a two-week review of the restrictions, due to take place on July 5, and to provide “clear assurance” he would lift restrictions earlier if the data supported it.

Despite the backlash, the Government comfortably won the vote to extend the lockdown regulations by 461 to 60, thanks to support from Labour and other opposition MPs. 

However, the size of the rebellion, the biggest since 53 Tory MPs voted against the regional tiers system last December, is likely to unnerve ministers. 

Six Labour and five DUP MPs also voted against the extension.

The rebels included former Cabinet ministers Karen Bradley, David Davis, Sir Iain Duncan Smith, Esther McVey and Chris Grayling, while Sir Graham Brady, the chairman of the 1922 committee, also voted against.

Social distancing, mask wearing and limits on numbers for sports events, theatres and cinemas will remain in place for now, nightclubs will stay shuttered, and people will be asked to continue working from home where possible.

What rules are staying after June 21 (Lockdown roadmap)

However, in a warning shot, a number of Tory backbench MPs, including former Business Secretary Andrea Leadsom, suggested their support in the future was conditional on Mr Johnson sticking to his word that there would be no further delays. 

Sir Robert Syms, another former minister, argued that remaining restrictions were “totally out of kilter” with some parts of the country, such as the South West, where hospital admissions remained extremely low.

And Sir Desmond Swayne, a veteran backbencher, said: “I could understand it if we were a communist party, but this is the party that inherited the true wisdom of the Whig tradition.

"This is the party of Margaret Thatcher, who said that liberty was indivisible. This is the party that only recently elected a leader that they believed, that we believed, was a libertarian, so there is much on which we are going to have to reflect."

Seeking to contain the backlash, Matt Hancock, the Health Secretary, said it was right to view July 19 as the “terminus”, adding: “On the basis of the evidence so far, I am confident that we will not need more than the four weeks to get this job done and to take step four."

He said that the four-week period would be used to fully vaccinate the “majority” of the 6.6 million people aged over 40 who had only received one jab, which he said would "save thousands of lives".

It would also allow all over-18s to receive their first dose, with Mr Hancock stating that the majority of people admitted to hospital in the past week with Covid-19 were “in the younger age group who had not yet had the chance to be vaccinated”, while just under one-fifth had received both jabs.

Mr Hancock went on to insist that the Government’s estimates did not show that a “further pause” beyond July 19 would “save many more lives, because of the level of protection for the over-50s.”

And he argued that there was a “material difference” in the state’s responsibility to protect people who had not yet been offered a vaccine, and those who had been but had chosen not to take it. By July 19, all adults will have been offered one.

By September, Mr Hancock said that Parliament would also return to normal, with MPs sitting “cheek by jowl” on their return from their summer holidays.

However, Mark Harper, the chairman of the Covid Recovery Group (CRG) of lockdown sceptic Tory MPs, said: “My worry, and the worry of others, is we’re going to get to this point in four weeks’ time and we’re just going to be back here all over again extending the restrictions."

Vaccination rates in the UK and the EU

Echoing his concerns, Chris Green, the Tory MP for Bolton West, said: “When the Prime Minister refers to a terminus, I fear he doesn’t mean the end. My fear is he’s thinking more of a bus terminus where we end one journey to start another.”

Steve Baker, the deputy chairman of the CRG, described the current situation as a "dystopia" and told the Commons: "We have transformed this society for the worse.

"We have put in place a culture of habits which will take years to shake off, culture and habits which distance people from one another and diminish their quality of life, the quality of relationships that they have with one another."

Sir Edward Leigh, the MP for Gainsborough, added: "This whole debate is a mortal threat to the Conservative Party. There’s been too much shifting of goal posts, too many fatuous rules based not on science, but on populism.

“Our society should be free and open, and there’s a real danger the public will increasingly ignore this. The Government will be a government of the emperor without clothes."