Coronavirus cases in England have “increased rapidly” with one in 240 people infected, Office for National Statistics data shows.
Covid Symptom Study app data also shows UK cases are rising, but at a slower pace than in early September.
The figures come as the government in England grapples with how to introduce new restrictions.
Science advisers warn hospital admissions are “very close” to levels in early March.
Ministers say cases are “getting out of control”.
The ONS estimates that 17,200 people a day are being infected in homes in England, with the highest rates in the North East, North West and Yorkshire and The Humber.
The organisation estimates that one in 500 people are infected in Wales and Northern Ireland.
The Covid Symptom Study app – which uses data from 4 million people and 12,000 swab tests – estimates 21,903 people are developing Covid symptoms every day across the UK.
That is 1,000-a-day more than a week ago.
Prof Tim Spector, who led the analysis at King’s College London, said: “We aren’t out of the woods yet, especially as hospital admissions are starting to increase, which we predict will continue to do so over the next two weeks.”
The rise in cases and people being admitted to hospital is causing mounting concern. New rules are expected to be announced on Monday and come into force on Wednesday.
The precise details are still being debated, but could include closing pubs and restaurants or a ban on overnight stays in some areas.
Data presented to MPs by England’s chief medical officer, Prof Chris Whitty, appears to put the hospitality sector in the firing line as parts of society such as schools and universities are being kept open.
Gillian Keegan, minister for skills and apprenticeships, said the government had to act to stem the rise in cases.
“This is serious – it is getting out of control, and we have to do something to bring it back under control,” she said.
Sir Mark Walport, a member of the Scientific Advisory Group for Emergencies (Sage) which advises government, told the BBC: “On the 19 March, just before the first set of widespread restrictions, hospital admissions were 586 in England and on the 6 October they were 524.
“So we are very close to the situation at the beginning of March.”
Sir Jeremy Farrar, another Sage member and director of the Wellcome Trust, says: “We are back to choices faced in the early March… the longer the decisions are delayed, the harder and more draconian are the interventions needed to change trajectory of [the] epidemic.”