Boris Johnson 'genuinely worried' Donald Trump could become US president

Boris Johnson said he was "genuinely worried" that Donald Trump could become US president as he described being mistaken for the tycoon as "one of the worst moments".

The Mayor of London, who has previously said the businessman turned would-be US president is "unfit to hold the office", said he was mixed up with the frontrunner for the Republican nomination during a trip to America.

"I am genuinely worried that he could become president," he told ITV's The Agenda with Tom Bradby.

"I was in New York and some photographers were trying to take a picture of me and a girl walked down the pavement towards me and she stopped and she said 'Gee is that Trump?'.

"It was one of the worst moments."