Boris Johnson has confirmed the proposed lifting of all lockdown restrictions in England will be put back by up to four weeks.

The Prime Minister announced this evening the setback to the final phase of his plan to end the lockdown next Monday due to concerns over the rapidly-spreading Delta variant first identified in India.

He told a Downing Street press conference that the spread of the Delta variant meant "we have obviously faced a very difficult choice".

Experts feared going ahead with Step 4 on June 21 as planned could lead to hospital admissions on the scale of the first wave of Covid-19 heaping unsustainable pressure on the health service.

To avert this, Mr Johnson said during a Downing Street press conference that it is "sensible" to put back the end of all legal limits on social contact to July 19, saying he is "confident" no further delay will be necessary.

He hopes deaths will be significantly reduced by that point because two-thirds of adults will have then been offered both vaccine doses due to the delay being coupled with a reduction in the time between jabs for the over-40s.

Limits on numbers for sports events, pubs and cinemas will therefore remain in place, nightclubs will stay shut, and people will be asked to continue working from home where possible.

Downing Street left open the option of ending restrictions on July 5 if the data proves drastically better than expected but conceded this is "unlikely".

Mr Johnson did, however, announce a limited easing of restrictions to take place from June 21 as he faces the prospect of a rebellion from Conservative MPs who are furious about the delay.

The 30-person cap for wedding ceremonies and receptions, as well as wakes, will be lifted, with limits to be set by venues based on social distancing requirements.

Care home residents will also no longer need to self-isolate for 14 days after leaving for visits in most cases.

Fans were expected to be able to attend the Euro 2020 semi-finals and final in Wembley as the pilots on attendance of large events continue.

Mr Johnson said: "It’s unmistakably clear that vaccines are working and the sheer scale of the vaccine roll-out has made our position incomparably better than in previous waves.

"But now is the time to ease off the accelerator because by being cautious now we have the chance in the next four weeks to save many thousands of lives by vaccinating millions more people."

Mr Johnson felt he had to delay the relaxation after at least one of his four tests to easing restrictions – that the risks are not fundamentally changed by new variants – had been failed.

Officials also called into question the test to ensure infection rates do not lead to a surge in hospital admissions that could put unsustainable pressure on the NHS.

Modelling by the Government’s Spi-M group suggested there was a possibility of hospital admissions reaching the heights of the first peak in March 2020 if the relaxation went ahead on Monday.

Experts believe the Delta variant is driving a rapid accelerations in cases, estimating it is between 40 per cent and 80 per cent more transmissible than the Alpha variant first found in Kent.

Ministers were expected to hold a vote in Parliament on Wednesday in order for the Government to be given the legal powers to extend the restrictions.