Sir Paul McCartney has revealed that one of his grandchildren was mugged at knifepoint.

The former Beatle said that robbers took his grandson’s phone in the recent incident in London.

He told The Times: “One of my grandkids, one of my older grandkids, was mugged and got his phone taken…

“He was saying the worst thing was that he should have just thumped the guy, he came back and felt a coward.

Sir Paul McCartney and his daughters Mary (left) and Stella
Sir Paul McCartney and his daughters Mary (left) and Stella (Carl Court/PA)

“I said: ‘No, no, no, no! The guy had a knife and you don’t know, the guy might be able to use that knife.’ So it is scary these days.”

The 77-year-old said that he was able to talk to his grandson because he had a similar experience, having been mugged in Liverpool when he was growing up.

“When I was a kid it was four guys and they nicked my watch. I was of a similar age,” Sir Paul told the newspaper.

“I just happened to be on my own, bigger kids came along and it was the same feeling.”

Sir Paul said he felt at the time: “‘I have got to learn karate and be a black belt – and then I’ll get ’em!’ It was the worst thing.”

The singer and musician, who is married to third wife Nancy Shevell and has penned a children’s book, has eight grandchildren, ranging in ages.

His eldest daughters Mary and Stella have four children each.