Coronavirus cases, deaths and hospitalisations have all increased in the past week as experts raise concerns about the UK's approach going into winter.
The latest figures from the government’s COVID-19 database show that cases have increased by 16%, deaths by 11% and hospitalisations by almost 7% in the last seven-day period.
On Monday, the government warned that winter will be “challenging”, insisting a spike in cases had been anticipated and saying it will keep a “close watch” on the situation.
The prime minister’s official spokesman said: “We obviously keep very close watch on the latest statistics.
“We always knew the coming months would be challenging.
“What we are seeing is case rates, hospitalisations and deaths still broadly in line with the modelling as set out a few months back now.
“But we will obviously keep a close watch on cases.”
But Professor Andrew Hayward, a government adviser and epidemiologist at University College London, said: “I think it’s concerning that we’ve got very high rates of infection and higher rates of hospitalisation and mortality than many of our European counterparts.”
Prof Hayward, a member of the government’s Scientific Advisory Group for Emergencies (Sage), told BBC Radio 4’s World At One on Monday: “We shouldn’t be complacent because there is still huge potential for the NHS to come under a lot of pressure and for there to be a lot of unnecessary deaths."
He said waning immunity is “probably part” of the reason why infections are currently high.
On Monday, there were a further 49,156 lab-confirmed COVID-19 cases in the UK. This is the highest number of daily reported cases since 17 July.
Watch: Highest number of daily COVID cases since July
It meant there were 309,013 cases in the last seven days, an increase of 43,079 – or 16.2% – on the previous week.
The number of weekly coronavirus deaths has also increased, up by 89 – or 11.4% – to a tally of 869 for the past seven days.
There were another 45 deaths recorded on Monday, bringing the UK total to 138,629.
The number of COVID-19 patients being admitted to hospital is also increasing, up 359 – or 6.9% – to 5,561 in the past seven days. The number of daily hospitalisations has reached 915, the highest level for a month.
The government has been criticised over what many see as the slow rollout of third booster jabs and vaccinations for 12- to 15-year-olds.
According to the latest bulletin from the Office for National Statistics (ONS), about one in 12 children aged 11 to 16 had coronavirus in the week up to 9 October, the age group with the highest infection rate in England.
The ONS data showed that one in 60 people had coronavirus in the seven-day period ending 9 October, up from one in 70 and one in 85 the previous two weeks.
Jabs for 12- to 15-year-olds were rolled out last month, but figures obtained by the PA Media news agency show that take-up for the age group in some areas is as low as 5%.
It reported that only 15 local authorities in England have managed to give a first jab to at least a quarter of 12- to 15-year-olds.
In Scotland, where children can already receive jabs in walk-in centres, the take-up is already more than 50% in half of local authority areas.
James Bowen, director of policy for school leaders’ union NAHT, said: “Allowing 12- to 15-year-olds to attend walk-in vaccination centres would be a sensible decision.”
The prime minister’s spokesman said: “In the first instance, we are allowing for the jabs to take place through the school immunisation services, this is the long-standing approach that has been used for flu and HPV jabs.
“We are working very closely with schools, we are going to keep the programme for 12- to 15-year-olds under review."
Under its autumn and winter plan, the government has suggested that some measures, including the mandatory use of vaccine passports and face masks, could be required if case numbers rise enough to put unsustainable pressure on the NHS.
But Downing Street said on Monday: “There is absolutely no plan to introduce Plan B currently.”
Watch: COVID vaccine rollout for 12- to 15-year-olds begins