Professor Chris Whitty said the number of cases in the UK is going up and pointed to tighter measures aimed at protecting the public, particularly the vulnerable and elderly.

It comes as Prime Minister Boris Johnson told reporters the UK will almost certainly move to the delay phase of tackling coronavirus.

Prof Whitty said: "We are now very close to the time, probably within the next 10 to 14 days, when the modelling would imply we should move to a situation where everybody with even minor respiratory tract infections or a fever should be self-isolating for a period of seven days."

Prime Minister Boris Johnson speaks during a press conference at 10 Downing Street on the government's coronavirus action plan (Photo: Alberto Pezzali/PA Wire).

Mr Johnson said he believed the UK could rise to the challenge posed by coronavirus.

He said: "While it is absolutely critical in managing the spread of this virus that we take the right decisions at the right time based on the latest and the best evidence, so we mustn't do things which have no or limited medical benefit, nor things which could turn out actually to be counter-productive, there is no hiding from the fact that the coronavirus outbreak will present significant challenges for the UK just as it does in other countries.

"But if we continue to look out for one another, to pull together in a united and national effort, I have no doubt that we can and will rise to that challenge."

Coronavirus: Anyone with cold or flu symptoms could be asked to stay home