Boris Johnson took a dip in an Alpine lake while Canada’s prime minister Justin Trudeau ran around it, after the men had joked about showing they were tougher than Vladimir Putin.

The Prime Minister swam in the Ferchensee lake near the Schloss Elmau resort in Germany where the G7 were meeting.

Mr Johnson and Mr Trudeau joked about Russian president Mr Putin’s history of shirtless photo opportunities, during a G7 session on Sunday, and the two leaders kept up their jokey conversation during their Monday morning exercise.

“He did go and have a swim this morning and he was very refreshed as he came in,” a Government source said.

“And it was an ongoing banter between him and Justin Trudeau because Trudeau sort of ran around the lake as the Prime Minister was swimming in it.

“So all this banter about riding bareback and imitating Putin and displaying their pecs got a new lease of life off the back of that.”