Boris Johnson has been forced to delay the end of England’s coronavirus restrictions by up to four weeks after being warned the move could lead to thousands of deaths and unbearable pressure on the NHS.

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

The leader of Norfolk County Council has said the prime minister had no choice but to delay the final step of easing Covid restrictions.

But Andrew Proctor, who leads the Conservative-controlled council said he knew people and businesses will be disappointed by the delay - with the county's crucial summer season nearing.

While case rates in Norfolk remain low compared to the national and regional average, they have risen by more than 50pc in the space of a week, with an increase in cases caused by the Delta (or Indian) variant.

In five of the seven Norfolk districts, the Delta variant makes up the majority of sequenced Covid-19 cases - Norwich, Great Yarmouth, Broadland, North Norfolk and South Norfolk.

Data from the Wellcome Sanger Institute shows over the two weeks to June 15 there were an average of 28 Covid cases caused by the Delta variant, compared to an average of 14 over the previous two weeks.

And Mr Proctor said the national statistics meant Boris Johnson had no alternative but to hang fire.

He said: “I fully understand that many people and businesses will be disappointed at this delay to the final step of easing restrictions and I hope that delay won’t be for too long.

“We want our economy to be opened up more, especially as we come into the summer months that are so important for Norfolk’s tourism industry.

“However, the government has always said it would follow data, not dates and on that basis, I can’t see that the prime minister had any alternative but to pause. Although Norfolk’s cases remain low, Delta variant cases are rising.

“The proposed month’s breathing space will enable more people to get vaccinated, which improves our long-term prospects of returning to a more normal life.

“It’s essential to get vaccinated when you are offered it. Also please keep following the advice – hands, face, space, regular lateral flow testing to reassure relatives, friends and colleagues.”

According to figures for the seven days up to Tuesday, June 8, case rates in Norfolk went up from 10.2 cases per 100,000 in the week up to Tuesday, June 1 to 15.5 cases per 100,000 - a jump of 51.6pc.

However, that remained below the East of England case rate of 32.6 cases per 100,000, which went up 56.7pc on the previous week and the England case rate of 63.9 cases per 100,000, which increased by 70.2pc from the 37.5 per 100,000 the week before.

In Breckland, case rates fell 10pc, from 21.4 cases per 100,000 to 19.3, while in Great Yarmouth they were down 12.5pc, from 8.1 per 100,000 to seven.

They also fell in North Norfolk, where the case rate fall from 11.4 per 100,000 to 7.6 was a drop of just over 33pc.

But in South Norfolk they were up 575pc, from 2.8 cases per 100,000 to 19.2 and in Norwich the rise from 6.4 cases per 100,000 to 18.5 was a 189pc increase.

They were also up 75pc in Broadland, from 12.2 per 100,000 to 21.4 and by 28.6pc in King's Lynn and West Norfolk, from 9.2 per 100,000 to 11.9.

The average number of daily new cases in Norfolk in the last seven days is 22, compared to 15.3 for the previous week - a 44pc increase.

The total number of people tested for Covid-19 in the last seven days is 24,641, compared to 22,612 for the previous week - an increase of nine per cent.

As of Saturday, June 12, there were three people who had tested positive for Covid-19 in hospital - none in critical care.

The number of outbreaks - defined as two or more linked cases - has fallen.

As of Sunday, June 13, there were 38 open outbreaks, compared with 42 the previous week.

Fifteen were in schools, four in care homes and care providers and 17 in businesses and workplaces.