Motorbike at the British Museum

The crowds that throng London's British Museum to peer and poke around Roman gods, Egyptian sphinxes and mediaeval relics have been distracted by a 21st-century motorbike, a mean machine prettily painted in red, pink and bright blue. It belongs to Grayson Perry, the potter, Turner prize winner, Royal Academician and now the curator of one of the most idiosyncratic and - surprisingly - moving exhibitions the museum has mounted: The Tomb of the Unknown Craftsman, which opened last week and runs until February 19. "It is a memorial to all the anonymous craftsmen who over the centuries have fashioned the man-made wonders of the world," he says. "I find their anonymity especially resonant in an age of the celebrity artist." The motorbike indicates a journey though the psyche of its owner and through the galleries and hidden corners of the museum. Not, Perry is quick to point out, the kind of journey used in the "tired metaphor of reality TV" but "a narrow pilgrimage across an infinite plain". Put simply, the artist has spent two years wandering the corridors of the museum seeking out artefacts from its collection of eight million pieces that resonate with his own works and obsessions. His themes include pilgrimage, shrines, maps and magic and the result is 35 - mostly new - works by him complemented by 190 artefacts chosen from the museum. But, says Perry, 51: "Don't look too hard for meaning. I am not a historian, I am an artist. I chose things for the way they looked." One part is given over to his childhood teddy bear, who is called Alan Measles, the "benign dictator of his fantasy world". In the exhibition he is "matched" by European coins with bear motifs, a carving of the Egyptian god Bes and the badge of a mediaeval pilgrim on horseback alongside Measles as a Quixote-like hero. Perry, with Measles riding pillion, went on a motorbike trip to Germany last year "to make peace with our old imagined adversary" so maps play a crucial part in the show. One of the first pieces he chose was an Egyptian woman's headscarf from 1964 showing an outline of the region as, perhaps envisioned by the leadership of the day, with territory stretching up to the Turkish border, down to Sudan and across Saudi Arabia. "I love maps and this was a no-brainer because it is so pertinent. With the Arab Spring the topography makes it a very odd object. We like to think we can trust maps but sometimes they are altered to suit the bias of the drawer. "And I like the fact that it is a headscarf as well," he says. The more time he spent in the museum, the more the past - and those anonymous craftsmen - exerted a hold on him. A 20th-century textile from Tibet depicting the cycle of reincarnation inspired him to create his tapestry Map of Truths and Beliefs, a mammoth work 6.9 metres by 2.9, which is based on a plan of the British Museum filled with names for the afterlife. The whole project is a careful chaos of mountain tops and perversely illustrated cities - Venice is represented as an industrial zone and Jerusalem as a coal pit. The work is dominated by a woman in folk costume and an angry black bear depicting raw emotion. "This is my mad map of pilgrimage," he says. "The museum is bound up with seeking meanings to things yet I think there is just as valid an alternative way of looking at the world which is more intuitive and as an artist that's what I have to go on. There is no map for me to follow so I interact with the world ... even if I get it wrong." The centrepiece to the exhibition is the Tomb of the Unknown Craftsman itself. A cast-iron ship, three metres long by two metres high, it is freighted with casts of objects from the museum - the Assyrian version of the Noah story on a cuneiform tablet, sphinx heads, coins, mummies, Buddhas, even the motorbike sneaks on board. It is sailing off on the last pilgrimage, a craft for the craftsman, and, just like the frayed little model of a boat buried in an Egyptian tomb three thousand years ago, it evokes a poem by DH Lawrence reproduced on the wall .... "and to build a ship / of death to carry the soul on the longest journey".