Nearly 3,000 people have tested positive for coronavirus in the UK for the second day running.
The 2,948 new cases on Monday came after 2,988 infections were reported on Sunday, the highest one-day rise since May, although the UK’s testing capacity is now far higher than four months ago.
The seven-day rate of new cases of Covid-19 in the UK has also risen above 20 cases per 100,000 people, according to the latest government figures.
In the seven days to 7 September, the rate stood at 21.3 cases per 100,000, up from 13.9 in the previous week.
A rate of 20 cases per 100,000 or above, if reported in other countries, is the level at which the government considers imposing quarantine conditions on people travelling to the UK.
Matt Hancock, the health secretary, called the surge “concerning” and under-25s, particularly those aged 17 to 21, accounted for a large number of positive cases.
He urged young people to stick to social distancing and warned failing to do so could put loved ones’ lives at risk.
“Don't kill your gran by catching coronavirus and then passing it on,” Mr Hancock told BBC Radio 1's Newsbeat on Monday.
The rise in cases comes after schools reported infections days after pupils returned to classrooms in England for the first time in March.
Schools in Suffolk, Middlesbrough, Hartlepool and Liverpool were among those affected by at least 46 cases, with hundreds of pupils forced to -self-isolate.
But Gavin Williamson, the education secretary, insisted the government was "very much" in control of the situation.
He said schools would only be closed as "absolute last resort".
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