England’s R rate is the highest it has been since January, with daily cases in the UK at their highest since February 27, the latest figures reveal.
On Friday, the weekly R rate estimate in England jumped to between 1.2 and 1.4, with the latest case figures showing the North West as the worst affected area.
Last week, the estimated R number was between 1 and 1.2 in England.
The latest R rate upper range to hit 1.4 was during the week of January 8, when it was estimated that England’s level was between 1.0 and 1.4.
New figures also show that the rate at which cases are growing in England is between 3 and 6 per cent per day, an increase on last week’s daily growth rate, which was 0 to 3 per cent.
Public Health England said on Friday that more than 90 per cent of new Covid-19 cases are now the Delta variant, which continues to show a significantly higher rate of growth compared to the Alpha (or Kent) variant.
Where is the Indian variant in the UK?
The latest figures from 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, or 240 per cent, from last week.
It estimates that the strain is 60 per cent more transmissible compared with the previously dominant Alpha 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."
She added: "It is particularly concerning that the increased transmissibility of the Delta variant is above the worst-case scenario modelled by Sage."
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.
Boris Johnson is due to make a decision shortly on whether England can go ahead with a full reopening on June 21, with an announcement expected on Monday.