CANNABIS use may still be outlawed in Britain, but there is another island in a parallel universe - peopled chiefly by British expatriates - where the rules are more relaxed.

The notional shores of Radio 4's famous desert island are, by now, surely plumed with smoke from the roll-ups of celebrity castaways. In the 56 years since Desert Island Discs was first broadcast, at least six guests have opted for the drug, or considered it, as their luxury item.

This month yet another joined the rebellious ranks. Eschewing the choice of a piano, currently number one in popularity, the psychologist Susan Blackmore asked for a supply of cannabis. Her request did not ruffle interviewer Sue Lawley, who seamlessly drew the programme to its accustomed close.

Later, a spokeswoman for the programme explained its policy on soft drugs: "It is the castaway's own island, you see, so they can make up the rules."

It was not always so. When Norman Mailer asked to take an endless supply of the drug with him, Roy Plomley, the programme's creator, gently refused. Use of an illegal substance was not to be condoned by the BBC. In 1982, the actress Pamela Stephenson's revelations about her LSD experiences were completely excised. Sir Peregrine Worsthorne, former editor of the Sunday Telegraph, caused a stir when he asked Ms Lawley for mild hallucinogens in 1992. However, by 1996, writer Hanif Kureishi's choice of marijuana seeds went almost unremarked.

The American lyricist Fran Landesman was not so lucky. Her request for a supply of the drug last year provoked a stream of complaints.

While the campaigning IoS must support those who have chosen, and will continue to choose, cannabis as their imagined solace, it would be churlish for the newspaper not to take its hat off to Desmond Tutu, who selected rum-and-raisin ice-cream, or to Arthur Scargill, who ordered the "Mona Lisa", and finally, with reservations, to composer Richard Rodney Bennett, for his domesticated choice of a circular knitting needle.