Boris Johnson is expected to announce a delay to the ending of social-distancing rules as the Delta variant continues to spread rapidly.

The ending of lockdown restrictions was set to take place on 21 June, but it is now expected that the Prime Minister will delay this by four weeks, with the BBC reporting that the decision had been signed off by senior ministers.

The move follows warnings from scientists that the rapid spread of the Delta variant first identified in India risks a “substantial” third wave if it is allowed to spread unchecked.

The Government ‘don't want to yo-yo in and out of measures’

Mr Johnson is expected to appeal to the public to show patience, with one last push to ensure that when controls do finally end it is “irreversible”.

He is thought to have spent Sunday evening (13 June) going through the latest data with the senior ministers and officials most closely involved in the process.

Chancellor Rishi Sunak, Health Secretary Matt Hancock and Cabinet Office minister Michael Gove were reported to have been briefed by chief medical officer Professor Chris Whitty and the chief scientific adviser Sir Patrick Vallance.

Latest daily government figures from Sunday showed another rise in Covid infections, with a further 7,490 lab-confirmed cases in the UK.

Rising infections in the UK are being driven by the Delta variant, first identified in India, which now accounts for 90 per cent of infections.

In England, there were a total of 35,971 positive Covid tests in the past seven days at a rate of 63.9 per 100,000 people.

However, the potential delay to the easing of restrictions has provoked a mixed response.

Foreign Secretary Dominic Raab told the BBC's Andrew Marr Show the government "don't want to yo-yo in and out of measures", and Professor Andrew Hayward from University College London, who is a member of the Sage group which advises the government, has also said that the easing of restrictions would "fan the flames" of rising infections.

Meanwhile, former minister Mark Harper, the chairman of the Covid Recovery Group (CRG) of Tory MPs, said any postponement would be a “political choice”.

Mr Harper warned that if the unlocking did not go ahead as planned, restrictions could carry on through the autumn and into the winter as other respiratory infections picked up.

He said: “The effectiveness of our vaccines at preventing hospitalisation means unlocking on June 21 could proceed safely. Any decision to delay will be a political choice.

“Variants and mutations will appear for the rest of time. We have to learn to live with it.

“If our very effective vaccines cannot deliver us freedom from restrictions, then nothing ever will.”