Queen Victoria among the drama queens

I wasn't holding my head in my hands - I was merely trying to shade my eyes from the spotlights to see who was asking a question the world's most photographed National Portrait Gallery, London, until October 23

Perhaps unwittingly, the National Portrait Gallery is falling into its own trap by calling its new exhibition The World's Most Photographed . Anyone who goes along on the strength of the title alone is going to be surprised to see Queen Victoria instead of Princess Diana, Elvis Presley and Muhammad Ali rather than Posh and Becks. And who would expect Audrey Hepburn to be in the top ten; some readers are no doubt already wondering, "Audrey who?"

They say the camera cannot lie. Indeed, the camera can only record what it sees. But that image can be incredibly distorted - by those who write the caption beneath it, place it out of context or show it in another light.

And, of course, the media can concoct a completely different picture from the one desired just by being selective.

I know what it is like to be at the receiving end. One of the most frequently used pictures of me, one that appeared everywhere after Beagle 2 went missing, showed a distraught scientist with his hands up to his temples in apparent anguish. Yet this was not taken at the time our spacecraft was expected to call home, but a lot earlier on a much happier occasion as Beagle 2 began its journey to Mars. I wasn't holding my head in my hands - I was merely trying to shade my eyes from the intense glare of the spotlights to see who was asking a question at a euphoric press conference. But the "distressed professor" fitted the news story at Christmas 2003 better than anything taken at the time when, for the sake of our team's morale, I refused to be downhearted.

Normally picture editors will trawl through tens (or hundreds now that we are digital) of photographs to find the one that matches the message they want to convey. Mostly, the media were exceedingly kind to me. But it can be very different: ask Cherie Booth, who is frequently embarrassed by the press using the most ghastly representations of her they can find.

The World's Most Photographed , on the other hand, focuses on how the subjects, or more likely their organisations, use photographs to create and sustain an image. Of course, not everyone here could strictly be described as "most photographed". Perhaps "most reprinted" might be more accurate. We get photographs we have seen thousands of times, such as Marilyn Monroe standing over the hot-air grating in The Seven Year Itch and James Dean's wrecked Porsche Spyder. These are juxtaposed with pictures that the subjects, or more likely whoever controlled the photographer, did not expect or intend us to see.

I guess the reason we can view them now is that 90 per cent of the subjects are dead. I cannot help but notice that premature death or a desire to become a recluse is a common factor among the chosen ones - such is the price of celebrity.

If you cannot get to London to see the exhibition, you can buy the book - which I recommend because the logic behind the selection of images is explained clearly. Or you can watch the BBC2 TV series.

Now my final gripe - why is Queen Victoria the only Brit in the exhibition? Surely, the same message could have been communicated using Winston Churchill, Margaret Thatcher and John Lennon instead of Adolf Hitler, Mahatma Gandhi and Greta Garbo? Surely, National Portrait Gallery, we still have some famous faces in Britain.

Colin Pillinger is head of planetary and space sciences, Open University.