He may have produced the most famous album cover of all time. But, for Sir Peter Blake RA, ubiquity is not its own reward. Thirty-seven years after he and his then wife created the cover of Sergeant Pepper's Lonely Hearts Club Band, the fact that they were paid a piddling £200 still hurts.

"Ever since, I have fought a vague kind of battle for some kind of fairness," the godfather of British pop art told the Guardian Hay festival yesterday.

Until recently, the battle had not been going altogether well. Five or so years ago, when the Apple label was preparing its Beatles anthology, Sir Peter was one of five artists asked to pitch a new cover design.

He turned the opportunity down. "I'm not going to audition," he said to Apple, who promptly told him they would rather have used David Hockney anyway. "That was the first insult," Sir Peter said. He then suggested that they use a com mission to "pay me a fee to solve the problem of Sergeant Pepper". But when he told the label how much the original fee was, Apple responded: "That sounds about right."

Sir Peter was not amused.

Now poetic justice may be on its way. Last year Sir Peter said in an interview that he would have preferred to have designed a cover for the Beach Boys' Pet Sounds - the other regular contender for greatest album of all time status - than for Sergeant Pepper.

"Brian Wilson's manager read it and asked me if I really meant it," said Sir Peter, "and he commissioned me to do a cover for Brian Wilson's new album." The forthcoming CD - Gettin' in Over My Head - is due out this month.

Explaining how the commission for Sergeant Pepper came about, Sir Peter said: "My dealer was a friend of the Beatles and the Stones, and he suggested they used a fine artist _ I talked to the Beatles at length about what the cover would be. I worked out it would show the moment after they had played in a bandstand in the park. My big contribution was the life-size cutouts, the magic crowds."

The numerous cutouts are of figures from Karl Marx and Oscar Wilde to Lewis Carroll and Marlene Dietrich. Shirley Temple, Sir Peter's childhood heroine, appears three times.

The 71-year-old artist has previously talked of retirement. But that would now seem to have been premature. "My new concept is that I am into my late period," Sir Peter said. "Most artists go potty as they get older: dafter and madder as they get more celibate. So I am consciously going to do that."

In that spirit, he is preparing a show for the Waddington Galleries in London in November. A section of it is to be called Marcel Duchamp's World Tour. It will comprise works featuring the great French painter, sculptor and writer in various situations, as he travels the globe in, according to Sir Peter, "an alumunium rock'n'roll tour bus".

"In one work Marcel Duchamp meets Tracey Emin in the desert, with three camp cowboys. In another he meets Elvis and the Spice Girls."