Prime Minister Boris Johnson urged Britain to lose “a little bit of weight” on Monday, using his own struggle with his weight before he contracted the novel coronavirus to encourage people to take more exercise.

His government unveiled a “Better Health” campaign on Monday, saying it would tackle the “obesity time bomb” by banning advertising of junk food before 9pm, ending “buy one get one free” deals and putting calories on menus.

“I’ve always wanted to lose weight for ages and ages and like many people I struggle with my weight, I go up and down. But since I recovered from coronavirus I have been steadily building up my fitness,” he said in a video clip on Twitter.

“I’m at least a stone down, I’m more than a stone down but when I went into ICU (intensive care) when I was really ill, I was way over weight ... and, you know, I was too fat,” he said, adding that he hoped the new campaign was not “excessively bossy or nannying”.

The Prime Minister has a reputation as a bon viveur, who in the past has spoken of enjoying an expensive bottle of red wine and late-night binges on chorizo and cheese. But he has also championed cycling to work and introduced so-called “Boris bikes” in London for public use when mayor of the capital.

Last month, Johnson said British people were fatter than most European counterparts apart from Malta and his government targeted “tackling the obesity time bomb”. The Labour Party said it had heard “big promises” from the ruling Conservatives before.