Dr Rosalind Eggo, a member of the Scientific Pandemic Influenza Group on Modelling (Spi-M) Government advisory panel, said with "very early evidence" showing that the current vaccines on offer "don't work quite as well against the Delta variant", it was important to increase the rate of second jabs. But some can affect the virus' ability to transmit between people.
This is the highest level since the week to April 16 and is up from 48,500 people - one in 1,120 people in private households - in the week ending May 22.
Jenrick said Portuguese scientists had detected the variant, but added: "What we don't yet know is how prevalent it is in Portugal - but more importantly than that, whether this really is a significant problem".
Within just a few days of having enough of each variant to study, they were able to analyze antibodies in the blood of 250 healthy people who received either one or two doses of the Pfizer-BioNTech Covid-19 vaccine, up to three months after their first dose.
The World Health Organisation says it is "not aware" of any new Nepal Variant of Covid-19.
Eleanor Riley, professor of immunology and infectious disease, University of Edinburgh, said: "These data can not tell us whether the vaccine will be any less effective at preventing severe disease, hospitalisation and death; we need to wait for the actual data on these outcomes".
"The critical thing is the impact on the number of people who end up in hospital for any given number of cases", he told Reuters after a meeting of G7 ministers in Oxford, central England, on Friday.
"You could of course wait whilst we do that research and then, God forbid, we learn that it is very virulent, that it does compromise our vaccines, or we can take a safety-first approach".
Experts say that delivering second doses promptly and providing boosters to those with weakened immune systems will help keep hospital admissions low.
At least 30 people dead after two express trains crash in Pakistan
Ghotki SSP Umar Tufail has confirmed the death toll, but has said that it may increase. "This is a challenging task". At least 75 people died when a train caught fire while travelling from Karachi to Rawalpindi in October 2019.
Elsewhere on Friday, it was announced surge testing is being rolled out in parts of Kent and West Yorkshire after cases of the Delta variant were detected.
It is possible the delta variant could threaten plans to lift lockdown restrictions by June 21, he said.
Professor Neil Ferguson, whose modelling was instrumental to the United Kingdom locking down in March 2020, said a "cautious" approach is needed as the Government balances the potential risks against a desire for normality. After genome sequencing, all five samples were found to be of the B.1.617.2 Delta variant. Sero surveys conducted past year in metro cities pointed out more than half of the population was immunised after recovering from SARS-CoV-2 infection during the first wave.
The latest R number indicates that on average every 10 people infected will infect between 10 and 12 others.
When the figure is above 1, an outbreak can grow exponentially, but when it is below 1, it means the epidemic is shrinking.
The UK Government has a deal with biopharmaceutical company CureVac to develop vaccines against future variants, and has pre-ordered 50 million doses.
According to the Telegraph, a two-week delay to the final stage of Boris Johnson's road map will be used to accelerate second jabs for over-40s, moving from a 12 to eight-week gap between doses, echoing the practise that is already in place for over-50s.
Figures published by Public Health England (PHE) show 608 cases of the Delta variant were recorded in Bedford by June 2. "This will reduce UK's rising risk from the Delta variant".