Covid infections and hospital admissions in the UK are at their highest level in months, officials said, as they warned people feeling unwell to stay away from vulnerable friends and family.
Data suggests about 1.3 million people, roughly one in 50, had the virus in the week up to September 26, the Office for National Statistics said.
The number was up from 1.1 million in the previous week.
Officials said there had been a “marked increase” in the number of cases among people over the age of 70 in England.
The estimates are based on random tests on people across the UK.
Sarah Crofts, ONS deputy director for the Covid-19 infection survey, said: "Infections have continued to increase in England, reaching levels last seen in mid-August.
"The rest of the UK is a mixed picture, with uncertain trends in Wales and Scotland and a recent increase in Northern Ireland.
"Amongst the over-70s there has been a marked increase in infections in England this week, a trend which we will closely monitor as the winter months progress."
The number of new cases represents the highest UK-wide total since the week to August 16.
But it is still some way below the 3.8 million weekly infections in early July, at the peak of the wave caused by the Omicron BA.4/BA.5 subvariants of the virus.
In London, the number of beds occupied by Covid patients has risen to its highest figure in six weeks.
In total, 1,228 beds were occupied by people with the virus as of October 5, representing a rise of 23 per cent in a week, NHS England said.
Covid admissions across the UK stood at 10.8 per 100,000 people, which was up 7.5 per cent in the previous week.
Admissions are currently highest among people aged 85 and over.
About two thirds of people with Covid are being treated for something else.
Dr Susan Hopkins, chief medical adviser at the UK Health Security Agency, said cases and hospital admission rates were at their "highest level in months".
She said the recent increases were concerning.
With outbreaks on the rise, she asked people to help protect the most vulnerable.
"If you are unwell, it is particularly important to avoid contact with elderly people or those who are more likely to have severe disease because of their ongoing health conditions.
"If you have symptoms of a respiratory infection, wearing a face covering will also help stop infections spreading," she said.
The number of outbreaks rose by 61 per cent, while the hospital admission rate also soared, climbing 45 per cent to 10.83 per 100,000 population, the UK Health Security Agency said on Thursday.
Hospital admissions were highest in the south-west of England, after increasing by 250 per cent since September, officials said.
Dr Hopkins urged residents to ensure they were up-to-date on their vaccinations and avoid contact with at-risk people if feeling ill.