Sir Paul McCartney has claimed it was he, and not John Lennon, who
He claimed the group's politicisation began after he met the philosopher Bertrand Russell in London in the mid-1960s.
But Sir Paul's critics see his comments as a further attempt to revise the history of the Beatles, casting himself in a better light.
"We sort of stumbled into things," Sir Paul told Prospect magazine.
"For instance, Vietnam. Just when we were getting to be well known, someone said to me: 'Bertrand Russell is living not far from here in Chelsea, why don't you go and see him?' and so I just took a taxi down there and knocked on the door."
He added:"He was fabulous. He told me about the Vietnam war – most of us didn't know about it, it wasn't yet in the papers – and also that it was a very bad war.
"I remember going back to the studio either that evening or the next day and telling the guys, particularly John [Lennon], about this meeting and saying what a bad war this was."