Johnson, who is hoping Britain can return to "normality" by Christmas despite fears of a second wave of cases over winter, insisted the country was getting better at tackling the virus.

The UK has been among the worst-hit countries in the world by COVID-19, registering the highest death toll in Europe.

Meanwhile, its economy has been battered by a months-long lockdown that has only been gradually eased over recent weeks -- and which Johnson is desperate to repair by avoiding another national shutdown.

"I can't abandon that tool any more than I would abandon a nuclear deterrent," he told the Daily Telegraph in a wide-ranging interview to mark the end of his first year in Downing Street.

"But it is like a nuclear deterrent, I certainly don't want to use it. And nor do I think we will be in that position again."

Johnson insisted health authorities were "getting much better at spotting the disease and isolating it locally" while also learning more about who it affects most and how it is spread.

The British premier on Friday sketched out a timetable for easing the remaining lockdown measures in England, including lifting homeworking guidance and reopening sports stadiums and live theatre.

Current government advice is for employees to work from home where they can, but under the new proposals employers will have "more discretion" to urge staff to return.

Despite Johnson's optimism and desire for a return to normal, his chief medical officer, Chris Whitty, said on Friday that social distancing needed to continue "for a long period of time".

The government's chief scientific advisor, Patrick Vallance, agreed, judging the risk of a second wave of infection to be "high".