ITV News Political Correspondent Dan Hewitt on whether the rise in cases is something the public should be concerned about
The Covid-19 infection rate in England has almost doubled in a week and is at its highest level since the week ending April 16, the latest Office for National Statistics (ONS) data shows.
Around one in 640 people in private households in the country had the virus in the week to May 29 - nearly doubling from one in 1,120 in the previous week.
It comes as the R number for England crept up too, with the figure now at between 1.0 and 1.2 (an increase of 0.1 from last week).
It means, on average, every 10 people infected will pass Covid-19 on to between 10 and 12 other people.
The country's growth rate remained at 0% to 3% - meaning the number of new infections could be increasing by up to 3% every day.
The latest ONS figures also suggest the increase in cases in England is linked to the Delta variant, first identified in India, the rise of which has prompted concerns over the planned June 21 easing of restrictions.
The Health Secretary said the government "always expected cases to rise" as lockdown was eased.
Matt Hancock told reporters the data was being watched "very carefully".
"Now, we always expected cases to rise as the country was opened up, the critical thing is the impact on the number of people who end up in hospital for any given number of cases," he said.
Health secretary Matt Hancock said the government remains "vigilant" about the Delta variant.
"That link has been broken by the vaccine, but it hasn’t been completely severed yet," he continued.
"That’s one of the things that we’re watching very carefully, and it’s too early to say what the decision will be ahead of June 21, but we’ll make sure people know in good time."
Experts have warned, however, that the Delta variant could be 50-60% more transmissible than the so-called 'Kent' variant.
Epidemiologist Dr Deepti Gurdasani told ITV News variant also causes more severe disease.
She described the rise in cases as "very concerning".
Epidemiologist Dr Deepti Gurdasani explains why a rise in Delta variant cases is concerning
Sarah Crofts, Head of Analytical Outputs for the Infection Survey, said the figures showed "a mixed picture" across the country.
"Analysing these trends will be key over the next few weeks as we monitor the impact of the variants in different regions."
In Scotland, Nicola Sturgeon said the country was at a "critical juncture" as daily new cases rose to their highest level since February.
"The position we are in now on that transition (to a less restrictive way of dealing with Covid) is a fragile one," the First Minister warned.
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"Many experts believe that, not just Scotland, but the UK is now at the start of a third wave of Covid
"Underlying all of this, and indeed driving this is the new Delta variant."
How have infection rates changed across the UK?
In Wales around one in 1,050 people in private households are estimated to have had Covid-19 in the week to May 29, the ONS said.
This is up from one in 3,850 in the previous week and the highest estimate since the week to April 16.
In Northern Ireland that measure was one in 800, broadly unchanged from one in 820 in the previous week.
For Scotland the figure was one in 680 people, broadly unchanged from one in 630.
How have infection rates changed around the country?
The percentage of people testing positive for Covid-19 is estimated to have increased in north-west England, the East Midlands and south-west England.
There are also signs of a possible increase in the West Midlands and London while the trend is uncertain for other regions, the ONS said.
North-west England had the highest proportion of people of any region in England likely to test positive for coronavirus in the week to May 29: around one in 280.
South-east England had the lowest estimate: around one in 1,490.
In many regions positivity rates remains very low.
It means trends are difficult to identify since they are affected by small changes in the number of people testing positive from week to week.
How has the R number changed across the country?
England - 1.0 to 1.2
East of England - 1.0 to 1.2
London - 1.0 to 1.2
Midlands - 1.0 to 1.2
North East and Yorkshire - 0.9 to 1.1
North West - 1.0 to 1.3
South East - 1.0 to 1.2
South West - 0.8 to 1.1