The United Kingdom, where at least 41,777 people have died with coronavirus, faces an exponentially growing death rate within weeks unless the government moves urgently to halt a rapidly spreading second wave, the country's senior medics said on Monday.

The UK already had the highest official COVID-19 death toll in Europe - and the fifth-largest in the world - while it wass borrowing record amounts in an attempt to pump emergency money through the damaged economy.

But new COVID-19 cases have been rising by at least 6,000 a day in the UK, according to week-old data, hospital admissions are doubling every eight days, and the testing system is buckling.

Chris Whitty, the government's chief medical officer, and Patrick Vallance, its chief scientific adviser, cautioned that if left unrestricted, the epidemic would reach 50,000 new cases a day by mid-October in the UK.

"If this continued along the path ... the number of deaths directly from COVID ... will continue to rise, potentially on an exponential curve, that means doubling and doubling and doubling again and you can quickly move from really quite small numbers to really very large numbers," Whitty said.

"If we don't do enough the virus will take off and at the moment, that is the path that we are clearly on and if we do not change course then we're going to find ourselves in a very difficult problem."

The virus is spreading across all areas of the country and less than 8 percent of the population have antibodies to the virus, though in London approximately 17 percent of the population may have antibodies, Vallance said.

Speed and action are urgently needed, Vallance and Whitty said, adding that as winter was approaching the COVID problem would haunt the UK for another six months at least.

Prime Minister Boris Johnson is due to speak on Tuesday.

Health Secretary Matt Hancock said the restrictions would be different from last time. The government wants to crack down on socialising but schools and many workplaces will stay open.

"If we do have to take action, it will be different to last time and we've learnt a huge amount about how to tackle the virus," he told ITV.

"Schools aren't where a lot of the transmission happens, it's more about people socialising," he said.

Asked about Christmas and if people would be able to hug their relatives, he said he wanted it to be as normal as possible.

"If this runs out of control now, we'll have to take heavier measures in the future," Hancock said.