Like medieval holy relics, Hollywood memorabilia multiply in order to meet the demands of the faithful

In 1984, Harrison Ford was being directed by Steven Spielberg in Indiana Jones and the Temple of Doom at Elstree Studios on the edge of London. Stephen, an ailing boy, was invited to the set one day to watch the filming. At one point, Ford surprised Stephen, and his mother, by presenting him with the bullwhip he had used in the film, two tickets to a preview of the film and a signed photograph. It bore the touching message: "Stephen - Get Well Soon! Best wishes - Harrison Ford." What a sweet gesture.

How do I know about this? Because I've been browsing through a Christie's catalogue of an auction devoted to "film and entertainment" which took place on 12 December. The estimate for the bullwhip, photograph and authenticating letter was £4,000-£6,000. I hope that Stephen did get better, and I'm sure that his mother was auctioning the items for a worthy cause, but still - was Harrison Ford making a kindly gesture, or was he offering a sort of voucher to be redeemed for money at some future date? No wonder celebrities are suspicious of their fans.

Some film stars - Paul Newman is a famous example - refuse to give autographs at all. I've sometimes wondered what the big deal is, but reading through the objects, pictures and documents in the auction catalogue, I came to sympathise with them. Paying money for an autograph might seem fatuous enough, but is there anything that can't be scavenged and sold? I remember a description, in Hunter Davies's biography of The Beatles, of the band's staff sitting in a hotel faking signatures on publicity photographs. But you could also bid for signatures, "some secretarial, some printed facsimile". I have never before heard the term "secretarial" used in this context, but I assume it means that the stars didn't do the signature themselves.

There are plenty of props for sale, too. As the experts say, provenance is everything. Remember that classic 1955 film, The Adventures of Quentin Durward? I didn't. Would you be tempted to make a bid for a sword "possibly used by Robert Taylor in the title role [my italics]"? That'll impress your friends. Or what about some helmets that were made for the movie of Flash Gordon in 1980? According to the catalogue, they are "similar to those worn by Klytus, the Hawkmen and Ming's forces [my italics]", but you do get Brian Blessed's signature "in blue ballpoint pen" thrown in.

In medieval times, holy relics were notorious for multiplying in order to meet the demands of the faithful. This can be true even of legitimate film props. Years ago, someone paid a fortune at auction for the ruby slippers worn by Judy Garland in The Wizard of Oz. Afterwards, an old studio employee pointed out that the MGM wardrobe department had manufactured dozens of them.

And Hollywood stars can be as silly as anybody else. In the last years of his life, one of the many people Orson Welles unsuccessfully approached for financial backing was Steven Spielberg. What made this - shall we say - ironic was that Spielberg paid substantial sums of money for the shooting script of Welles's Citizen Kane (which he keeps in a glass case in his house) and for the sledge from the film.

This last acquisition reminds me of the joke about an American tourist on holiday in Ireland, who is offered the skull of the Irish hero Brian Boru. The tourist protests that he has already bought a skull of Brian Boru and that, besides, this one is smaller. "Ah," says the Irish vendor, "this is Brian Boru when he was a boy."

To buy the so-called "sledge from Citizen Kane" is hardly less absurd, because at the very end of the film, in what must be one of the half-dozen most famous moments in film history, you see the bloody thing being burnt. And to make it even more absurd, Spielberg himself parodied the scene at the end of Raiders of the Lost Ark.

One sunny summer day when Rudyard Kipling was an old man, a friend walked to visit him at Bateman's, his Jacobean house in Sussex. As the friend approached, he was surprised to see smoke billowing from the chimney. He entered Kipling's study to find him feeding handfuls of letters and documents into the fire. He looked round and said: "Nobody's going to make a monkey of me when I'm dead."

What a terrible act of vandalism. As a result, all we have left of Kipling are his books. Lucky us, I'd say.