Britain reported another 131 coronavirus deaths on Tuesday as it recorded its highest daily death toll since March.
The country also recorded 23,511 new Covid-19 cases, making it the seventh consecutive day where infections have fallen.
The reversal after weeks of rising rates has coincided with the removal on July 19 of nearly all pandemic rules in England, including legal requirements for social distancing wearing a mask in public indoors.
The surprising drop has confounded the government and scientists, who had previously warned cases could reach as high as 100,000 cases per day.
Despite the turnaround, which comes after the start of summer school holidays, ministers are warning the long-term situation remains uncertain.
"I have noticed that obviously we have six days of some better figures but it's very, very important that we don't allow ourselves to run away with premature conclusions about this," Prime Minister Boris Johnson said on Monday.
The country's successful vaccine rollout is believed to part of the reason for the sudden drop in cases. So far, 71 per cent of the population has received a second dose, one of the highest figures in the world.
Imperial College epidemiologist Neil Ferguson said the end of Britain's pandemic could be just months away as vaccines have so dramatically reduced the risk of hospitalisation and death.
"We're not completely out of the woods but the equation has fundamentally changed," Ferguson, whose modelling of the virus's likely spread at the outset of the pandemic in early 2020 alarmed governments across the world, told the BBC.
“We will still have Covid with us, we will still have people dying from Covid but we will have put the bulk of the pandemic behind us.”
“Cautiously, I think it might be over at the end of the summer,” he said. “It’s perfectly reasonable to suggest that we could get herd immunity in a few months because at the moment people who are refusing to be vaccinated are becoming infected at a much higher rate.
“So we might be done by the end of the summer, but I think it's fair to say that nobody really understands why.”