A bloke I knew on a building site had the name "Freddie" tattooed on his upper arm. After a long day at the cement mixer, I dared to ask him about it. "It's in case I get so pissed I can't remember who I am," replied Freddie.
Tattoos are fashionable; to this extent, they are a way of joining in. But they also have a history of identifying people, of marking them out, so to speak. After the mutiny on The Bounty, the naval courts martial relied on the evidence of tattoos to make sure they were trying the right men. Among the traitors, who had lived with the highly decorated inhabitants of Tahiti, going native had been carried to epidermal extremes. The story of Fletcher Christian, warts and all - or buttock tattoos and all, in his case - is one of the lurid features of "Skin Deep", an exhibition at the National Maritime Museum which will be receiving its first visitors as you read this.
Disappointingly, you can't see tattoos in the flesh at Greenwich. But there are drawings from Captain Cook's voyages, and wooden mannequins etched with designs including those of Te Rangitu Netana, the Polynesian who is personal engraver to the stars. Thanks to him, Robbie Williams was feeling a little prick long before the reviews for Swing When You're Winning came out.
In the 19th century, as word spread of the exotically punctured form of the Prince of Wales, tattoos became distinguished marks. Nor has the body politic been neglected: Winston Churchill had an anchor on his arm. For Karin Buch-Nielsen, the curator of the exhibition, periods when body art have been out of favour are merely stitches in time. Even the Iceman, a shepherd from 2,000 years ago whose frozen remains were discovered in the Alps in 1991, had been pricked and patted on his petrified hide.
One aspect of the show is to follow the tracks of the tattoo, from south-east Asia to the Royal Navy and the merchant marine, and finally into society at large. Some of us believe that tattoos belong nowhere else but on the persons of matelots and jack tars (in the same way that gypsies are the only men who can carry off earrings). When I propose this to Buch-Nielsen, she says: "Yes, but among the officers at sea, tattoos were not very well seen, even for those who came up from the lower ranks."
In this retrospective of fleshy couture, a story about class can be discerned just beneath the skin. Despite traces of blue blood on the stylist's needle, the tattoo parlour has been filled mainly by the working classes. Buch-Nielsen says: "In the 1960s, for example, it was completely normal for the average man to have tattoos." If you have the diary handy, "Skin Deep" runs until September: ink it in.
"Skin Deep" is at the National Maritime Museum, London SE10 (020 8858 4422), until 30 September