The rise in coronavirus cases across England, with up to 96% of new cases estimated to be the Delta variant, should be ringing “alarm bells” ahead of lockdown being lifted, ministers are being warned.

The latest figures from Public Health England (PHE), published on Friday, show that 42,323 cases of the Delta variant first identified in India have been confirmed in the UK, up by 29,892 from last week.

It estimates that the strain is 60% more transmissible compared with the previously dominant Alpha, or Kent, variant, and that cases are doubling every four and a half days in some parts of England.

The All-Party Parliamentary Group (APPG) on Coronavirus chairwoman Layla Moran said the figures should “set alarm bells ringing in Government”.

The Lib Dem MP added: “These figures should set alarm bells ringing in Government as we approach June 21.

“The Government must immediately explain to the public whether this exponential growth suggests the country is in line for a severe third wave, and if so what it is doing to prevent this.”

Meanwhile, Labour warned that the pace of the variant’s spread put the potential lifting of lockdown restrictions at risk.

Shadow home secretary Nick Thomas-Symonds said: “The pace at which cases of the Delta variant continue to rise is deeply worrying and is putting the lifting of restrictions at risk.

Cumulative UK Covid-19 vaccinations
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“The blame for this lies with the Prime Minister and his reckless refusal to act on Labour’s repeated warnings to secure our borders against Covid and its variants.”

However, Downing Street has defended its borders policy in relation to the Delta variant.

Asked whether Boris Johnson regretted not putting India on the red list of travel restrictions sooner the Prime Minister’s spokesman said: “I would point to the tough border measures that we’ve had in place for a fair amount of time now, that we’ve ensured that anybody arriving from India needed to quarantine at home, and then later as you said they were put on the red list which means that people have to quarantine in a hotel if they arrive in the UK from India.”

Their comments come after The Times reported ministers are considering a four-week delay to what some are calling “freedom day”, in order to give businesses certainty and allow more time for people to receive both vaccine doses.

Boris Johnson is due to make a decision shortly on whether England can go ahead with full reopening, with an announcement expected on Monday.

The Prime Minister is being urged to err on the side of caution and delay the next stage of his road map as new figures show cases rising across England.

Covid-19 vaccine doses in the UK
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The latest Office for National Statistics (ONS) figures estimate that around one in 560 people in private households in England had Covid-19 in the week to June 5, up from one in 640 in the previous week and the highest level since April 10.

PHE said that growth rates for Delta cases are high across all parts of England, with regional estimates for doubling time ranging from 4.5 days to 11.5 days.

As of June 7 there have been 42 deaths in England of people who were confirmed as having the Delta variant of Covid-19 and who died within 28 days of a positive test, 23 of which were unvaccinated.

The figures also showed that two thirds of the 1,234 people who attended A&E in England between February 1 and June 7 and who were confirmed as having the Delta variant of coronavirus were unvaccinated.

Of the 383 cases where attendance at A&E resulted in an overnight admission, 251 (66%) were unvaccinated.

Vaccines minister Nadhim Zahawi stressed the importance of being “really careful” in lifting coronavirus restrictions and urged against “squander(ing) those hard-fought gains” made by the vaccination programme.

During a broadcast round on Friday morning, Mr Zahawi emphasised that the virus “hasn’t gone away” when asked about reports of a delay.

“There have been some really hard-won battles against this virus and we don’t want to squander those hard-fought gains that we have made through the vaccination programme,” he told Times Radio Breakfast.

“In saying that, the virus hasn’t gone away, the virus will continue to attempt to mutate, to escape, to try and survive, and I think it’s really important that we are really careful.”

Mr Zahawi said the Government was “on track” to meet a target of all over 50s being offered their second jab by June 21, as he appealed to those who had not had a first dose to come forward to be vaccinated.

Adults who have received Covid-19 vaccine
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Reports of a four-week delay to June 21 were welcomed by Jim McManus, vice-president of the Association of Directors of Public Health, who is warning that lifting restrictions risks cases and hospital admissions rising further.

Mr McManus told BBC Radio 4’s Today programme: “If you get enough people infected, you will get a rise in hospitalisations.

“You will also get a significant rise in long Covid, which is something we want to avoid too.

“The second thing is that the more people infected, the more variants will develop, and the more risk we have that a variant will develop that evades the vaccine completely.”