Boris Johnson urged people to “exercise extreme caution” as they celebrate Christmas amid fears about the spread of coronavirus.

The relaxation of social distancing rules across the UK is expected to go ahead despite warnings about the possible impact on efforts to control the virus.

But while the original UK-wide plans would have seen three households allowed to form a festive bubble between December 23 and 27, Wales will now limit that to two households.

Talks involving the UK Government and leaders of the devolved administration agreed to continue with relaxations, but with a stronger message warning people of the dangers.

At Prime Minister’s Questions Mr Johnson said it was right to “stress the importance of people taking care this Christmas”, particularly due to the risk of asymptomatic transmission of coronavirus.

He told MPs: “We should exercise extreme caution in the way we celebrate Christmas.

“We can celebrate it sensibly but we have to be extremely cautious in the way we behave.”

Talks took place on Tuesday and Wednesday involving the leaders of Scotland, Wales and Northern Ireland and Cabinet Office minister Michael Gove.

Mr Johnson told MPs there was “unanimous agreement” across the four nations “that we should proceed in principle with the existing regulations”.

“We don’t want to criminalise people’s long-made plans,” he said.

“But we do think it’s absolutely vital that people should – at this very, very tricky time – exercise a high degree of personal responsibility, especially when they come into contact with elderly people, and avoid contact with elderly people wherever possible.”

As Mr Johnson claimed unanimity across the four nations, Welsh First Minister Mark Drakeford set out his decision to deviate from the joint approach.

He said: “Here in Wales, the position is that only two households should come together to form an exclusive Christmas bubble during the five-day period.

“The fewer people we mix with in our homes, the less chance we have of catching or spreading the virus.

“None of us wants to be ill this Christmas. And we don’t want to give coronavirus to our close family or friends.”