Boris Johnson has suggested that journalists are “always abusing” others and that “guilt” led him to swap the profession for politics.
The prime minister made the comments while speaking to a group of schoolchildren.
He told them: “When you are a journalist you think, ‘Great, great job...’
“But the trouble is that … sometimes you find yourself always abusing people or attacking people.
“Not that you want to abuse them or attack them but you are being critical … where maybe you feel sometimes a bit guilty about that, where maybe you have not put yourself in the place of the person you are criticising. And so I thought I would give [politics] a go.”
But he added that he was in his mid-30s before he went into politics, and that his “strong” advice would be to do something else first.
The prime minister’s press secretary Allegra Stratton denied his remarks were a comment on press reports about his fiancee Carrie Symonds.
Ms Stratton told a Westminster media briefing: “That is the prime minister talking about the fact that for all of you as journalists, your job is to constantly challenge and that’s something that makes all of us in government better. The role of journalism is to constantly be asking the details and the finer points, as you have done on the roadmap.”
Mr Johnson gave his views on journalism while on a visit to a south London school.
During his long career in journalism Mr Johnson worked as columnist for The Daily Telegraph and was editor of the Spectator magazine.
While serving as mayor of London he infamously dismissed the 250,000 a year he earned from his second job writing columns as “chicken feed”.
His columns themselves also proved controversial, including in 1998 when he referred to gay men as “tank-topped bum boys”.
He was also criticised for calling black people “piccaninnies” and describing them as having “watermelon smiles”.
Labour called on Mr Johnson to apologise for today’s remarks.
Chris Matheson, Labour’s shadow media minister, said: “For Boris Johnson to say journalists are ‘always abusing people’ probably says more about his own career.
“It is particularly troubling coming so soon after the prime minister stood by one of his ministers who attacked a journalist who was just trying to do her job.
“We know from Donald Trump that these kinds of assaults on the free press are dangerous and designed to stir up distrust and division.
“Boris Johnson should withdraw these remarks and apologise.”