The UK has announced more than 10,000 daily coronavirus cases for the first time since mass testing began.
There were 12,872 new cases, while a further 49 people have died within 28 days of testing positive for Covid-19.
However, the government said a technical issue meant previously-unannounced cases from the past week had been added to the day’s total.
It comes after data released this week suggested infections may be increasing more slowly than in previous weeks.
This data was based on weekly testing among a sample of people in the community to get an idea of how many people in England have the virus at any time.
But the government also closely watches the daily number of positive cases, as it provides the most up-to-date snapshot.
However, it published a cautionary message on its “data dashboard”, explaining that the totals reported over the coming days would include some cases from the previous week, “increasing the number of cases reported”.
The daily total saw a significant rise from 4,044 on Monday to a then-high of 7,143 on Tuesday. However, over the next four days the daily total remained stable – varying between 6,914 and 7,108 – before the big leap in numbers announced on Saturday.
The figures announced on Saturday would also have been partially inflated by the fact that 264,979 tests were processed the previous day, the third highest there has been so far in a single 24-hour period.
Saturday’s figure brings the total number of recorded cases in the UK to 480,017.
On the same day, France recorded 16,972 new cases – a new daily high for the country.
On Saturday tighter restrictions came into force in parts of northern England after a spike in coronavirus cases.
It is now illegal to meet people indoors from other households in the Liverpool City Region, Hartlepool, Middlesbrough and Warrington.
It means than a third of the UK is now under heightened restrictions.
The new rules come as hundreds of Northumbria University students are self-isolating after testing positive for Covid.
Elsewhere, people arriving in the UK from Turkey and Poland now have to quarantine for two weeks.
The new rules – which also apply to the Caribbean islands of Bonaire, St Eustatius and Saba – came into force at 04:00 BST on Saturday.
After a steady decline since the first peak in April, confirmed coronavirus daily cases in the UK have been rising again since July, with the rate of growth increasing sharply from the end of August.
Sage, the body which advises the UK government, say it is still “highly likely” the epidemic is growing exponentially across the country.
Their latest R number estimate – indicating how fast the epidemic is growing or falling – rose to between 1.3 and 1.6.
But an Office for National Statistics (ONS) survey estimates there were 8,400 new cases per day in England in the week to 24 September – slightly down on the previous week’s estimate of 9,600 daily cases.
The ONS’s estimates of how much of the population is currently infected are based on testing a representative sample of people in households with or without symptoms.
It is different to the number published daily by the Department of Health. That records positive cases in people with potential Covid symptoms who request tests.