IB: Lennon is absolutely an art school person.

TB: And Mick Jagger and some members of Queen were out of art school, too. This is in answer to Ian's point about pop musicians not wanting to work with artists. But I think many of the more sophisticated or ambitious of them, people like Bowie and even the Rolling Stones and the Beatles, have ambitions which plug into a wider cultural context. Others are very modest in terms of ambition; an extreme example would be Larry Parnes's stable of rock 'n' rollers from the early 1960s, called things like Duffy Power and Vince Eager. Cliff Richard came out of that too.

IB: But that's performance art, in a way, more than music. The Sergeant Pepper thing was a bit of performance art, it was all about dressing up in funny costumes, and presenting a whole thing.

TB: It would be now, because they'd put it on a DVD, but in 1966 it had to simply go on a vinyl record, admittedly with a very striking cover.

DJ: Just to go back to where we started, on the political role of rock stars, do you think they get bored? Perhaps partly for the reasons that you suggested: that the music doesn't really progress very far. You do your thing, and that's it - all people really want is for you to do it again and again. So some of these people then seem to want to save the world; they feel that having created their musical product, they then owe something to society, or they have to become something else, go beyond being musicians, to become messiah figures.

TB: That's a very generous interpretation of their motivation. I think it's in part because they're fawned on and flattered by the politicians. It starts with Harold Wilson back in 1964, giving the presentations to the Beatles, and cuddling up to them, to acquire some of their charisma by osmosis, which he badly needed. It goes on right into the present day. If, for example, when Blair invites Noel Gallagher round to 10 Downing Street to meet him after the 1997 election, and tells him how wonderful he is, he begins to think, "Perhaps I'm not just a rock'n'roller after all, I'm someone more important than that." So I think it's because of the politicians, and the press, in particular, who fawn on them and tell them that what they're doing is not just recreation.

IB: I wonder if it works politically - I can't believe it had any effect on Blair except to make him look slightly ridiculous. In fact, it wasn't really Blair being politically canny, it was Blair's vanity that he was wrapped up in, and it actually made him feel very good about himself, to feel that he could mix with these people.