The number of coronavirus deaths in the UK rose by 37 on Tuesday, marking the largest daily increase in two-and-a-half months.
Data released via the government’s coronavirus tracking website showed that 37 deaths were recorded, 26 more than the 11 new deaths reported on Monday.
The increase is the highest since 9 July, when there were also 37 deaths at a time when lockdown restrictions were starting to be eased across the UK.
The number of cases also rose by 4,926, the biggest daily increase since 1 May when the number of people being tested for the virus was far lower.
It brings the total number of cases nationwide to 398,625 so far.
Watch: UK coronavirus cases passes 400,000
It comes as Boris Johnson said the UK had now reached "a perilous turning point" in the face of a second wave of COVID-19 cases.
The prime minister announced a host of new measures on Tuesday aimed at controlling the recent rise.
Johnson warned new coronavirus restrictions could last six months, with office staff working from home, the wider use of face masks and a 10pm curfew on pubs and restaurants.
Read more: Scotland bans households from visiting each other in stark contrast to Boris Johnson’s new rules
He said that the new curbs could continue well beyond Christmas and New Year "unless we palpably make progress" in controlling the spread of the virus.
The PM also announced tougher enforcement measures, with businesses facing fines or closure for failing to comply with coronavirus rules, and people facing £200 penalties for failing to wear masks where required or breaching the so-called "rule of six".
Watch: Restrictions could remain for six months says PM
The military could be brought in to free up police officers to tackle coronavirus rulebreakers, the Prime Minister said.
Despite the extra measures, Johnson insisted they did not amount to a second lockdown.
"This is by no means a return to the full lockdown of March, we're not issuing a general instruction to stay at home, we will ensure that schools, colleges and universities stay open, because nothing is more important than the education, health and wellbeing of our young people," he said.
But he warned that tougher measures may be needed if the R number, the average number of people someone with COVID-19 infects, remains above one.
"I must emphasise that if all our actions fail to bring the R below one then we reserve the right to deploy greater firepower with significantly greater restrictions," he warned.