Boris Johnson confirmed the final stage of England’s roadmap – due to end on June 21 – will be delayed by four weeks amid fears the NHS could be overwhelmed by the spread of the Indian or Delta variant. .

It comes as the Government won the vote to extend lockdown regulations until July 19, despite backlash from 49 Conservative MP’s who voted against the continuation of measures.

In what is believed to be the second largest Tory rebellion of the pandemic, Boris Johnson was accused in Parliament on June 16 of “shifting the goalposts” and was 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.

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.

But there are some exemptions, with the cap on wedding guests no longer applying. Instead, individual venues will have their own Covid-secure capacity limits.

Weddings rules

Care home residents who leave a site will also not have to self-isolate for 14 days on their return, a change some campaigners have been seeking.

It comes as the Covid reproduction ‘R’ number has risen to 1.4, but vaccinating younger people should slow down the exponential rise in cases, scientists believe.

As per the rest of the roadmap journey, an update will take place two weeks into the four-week delay, to see whether the Covid situation has improved. However, Downing Street officials said it was "unlikely" the plan would change then.

Number 10 sources said Mr Johnson was "confident" that only a four-week delay will be needed, although doubts remain given the sharp rises in Covid cases and hospitalisations, with the PM calling July 19 a "terminus" and not giving a ‘cast iron guarantee’ that lockdown measures will end on this date.

Cases would reach the January peak next month

The decision was taken after scientific modelling for the Government suggested a third wave of cases could see hospitalisations hit the peak seen in the first wave.

But it has emerged that modelling used by the Government to push back the June 21 reopening was based on out-of-date estimates of vaccine effectiveness, which assumed far fewer people protected by the jabs.

Under the most pessimistic scenario, Imperial College estimated Britain could experience a further 203,824 deaths by next June, while even modest estimates from other groups suggested more than 50,000 would die.

Imperial was working on the basis that the AstraZeneca jab would reduce hospitalisations by between 77 and 87 per cent after two doses, while the London School of Hygiene and Tropical Medicine (LSHTM) suggested 81 to 90 per cent, and the University of Warwick put it a little higher – between 86 and 95 per cent.

But we now know from real-world Public Health England (PHE) data that the AstraZeneca jab is 92 per cent effective against hospitalisation. 

However, alarms were raised about the Delta variant, which has become the dominant strain of new virus infections in the UK. 

The latest scientific analysis suggests the variant is between 40 per cent and 80 per cent more transmissible than other Covid strains.

Downing Street is arguing that the four-week delay allows the Government to vaccinate millions more people, with the rollout strategy tweaked in an attempt to maximise protection.

The target for offering the first Covid vaccine dose has been brought forward from the end of July to July 19, meaning all adults should be offered at least one jab by the new final reopening date.

People in their 40s will also now only have to wait eight weeks rather than 12 between the first and second jab, which provides the maximum immunity. That matches the rules for people aged 50 and over. 

The NHS will contact people in their 40s who are now eligible for their second jab as a result of the change.

How many more could we vaccinated with the delay to June 21?

No changes to the travel rules were announced. A review of the Covid borders rules is due later this month, with checks on whether new countries can be added to the green list – for which no quarantine on return to the UK is required – happening every three weeks.

However, summer holidays abroad will be opened up for vaccinated Britons under plans being considered by the Government, The Telegraph understands.

Officials are drawing up proposals that could allow people who have had both Covid jabs to avoid having to quarantine on their return from amber list countries, although they will still have to be tested.

The change would effectively turn amber countries green for the vaccinated, opening up the possibility of quarantine-free travel to most major holiday destinations in Europe and the US.

The Treasury is not announcing any new financial support despite the four-week delay, to the frustration of business industry leaders who have demanded extra help.

From next month the Government will cover only 70 per cent of wages of furloughed workers instead of 80 per cent, with businesses having to pick up the extra 10 per cent.

Hospitality and leisure companies will also have to start paying a third of their business rates bills from the start of July, ending more than a year of their rates being waived.

A Treasury source argued that more than £1 billion of grants are still available for companies – especially nightclubs, which cannot open – affected by the pandemic from local authorities. "We need to keep a balance in order to ensure we can recover strongly," the source said.