DIARY: Karmarama's T-shirt hits Charles Saatchi's trendy art credentials

Most of you plebeians reading this will probably not know that graffiti is once again the thing of the moment. Forget art, forget music and forget film - spraying buildings with hard-to-remove aerosol paint is where it's at.

And if graffiti is the thing of the moment, then Banksy is the man of the moment. This modern-day Scarlet Pimpernel bamboozled local artists everywhere when, heavily disguised, he snuck into the Tate Modern and secretly hung some of his work on the wall.

This was more than just opportunism. The art world has been quite taken with Banksy. Many consider him to be an artist of note and would tell him so if they only knew who the hell he was (Banksy keeps his identity secret so as to avoid prosecution).

One such fan is Charles Saatchi. Britain's "Mr Modern Art" is a long-time admirer of Banksy, so imagine his glee when, at an exhibition in Hoxton last month, he spied a young fellow wearing a T-shirt saying: "Arrest Me I'm Banksy."

Within seconds, Saatchi accosted him and congratulated him on his work.

Repeatedly. Alas, it wasn't Banksy at all but a Fine Art student named Jet Rands. And his T-shirt was a fabric of lies designed by the ad agency Karmarama.

Oh well. Better luck next time, Charlie.

Apparently, the T-shirts will soon be widely available, so if you've ever wanted to be accosted by Nigella Lawson's husband, now's your chance.