Von Ribbentrop in St Ives, Kettle's Yard, Cambridge

Andrew Lanyon plays with his viewers in a show that gleefully sacrifices accuracy to imagination

Tug on one of the wooden curtain-rings that dangle beside many of the vitrines in Andrew Lanyon's new show, Von Ribbentrop in St Ives, and any one of a number of things might happen.

A black-gloved hand may jiggle obstetrically in a puppet-shaped cut-out, or a red light, apparently intended to emulate gunfire, may flicker through a keyhole. Then again, tugging could cause the door of a tiny wardrobe to slide open just a crack, or a semi-transparent grid to move fractionally so that bombs falling from the cartoon aircraft behind it become ack-ack shells shooting upwards.

Actually, you'll have to take the last one on trust since, as far as I could see, pulling on this particular ring has no optical outcome at all. The grid did at least move, but absolutely nothing happened when I tugged on some of Lanyon's strings, his dramas-in-boxes being disarmingly prone to failure. In other circumstances, this might be annoying. In this exhibition it seems only apropos, the subject of Lanyon's show being accident.

The idea that Joachim von Ribbentrop might ever have holidayed in St Ives sounds like a joke in poor taste, but no: Hitler's ghastly ambassador to the Court of St James stayed in the village in 1937, while on a tour of Cornwall. The Führer had offered him St Michael's Mount after an eventual English surrender, and the future Nazi foreign minister was checking out his seaside-cottage-to-be. This is bizarre enough, but there was worse.

In 1927, Ben Nicholson had met a slightly deranged ex-sailor called Alfred Wallis in St Ives, and the meeting changed his life. Something about Wallis's naïve, boat-paint-on-cardboard images struck a note with the world-weary Nicholson, and his own work became more two-dimensional, simplified. In 1934, Nicholson met Piet Mondrian in Paris, and that meeting pushed him further along the road towards the pure abstraction which marked his art of the mid-1930s. St Ives became (and, for half a century, remained) a hotbed of English Modernism. In July 1937, Joseph Goebbels' exhibition of "degenerate art" opened in Munich, aimed at purging modernism from Aryan culture; the Entartete Kunst show included two Mondrians. Thus it was that the man sent to bring Nazism to Britain and the man who introduced the British to Mondrian found themselves in the same Cornish village at the same time.

It's worth pointing out that Lanyon's aforementioned curtain-rings are hung from elasticated thread, which is also apropos. The overlap of Nicholson and his German adversary is by no means the only historical accident in Von Ribbentrop in St Ives, nor even the most unlikely. Lanyon's aim is to tax our belief, to see how far he can stretch our credulity before we snap and say, "Oh, come on."

Thus he cheerily points out that a German bomb hit the Porthmeor gas holder on 8 August 1942, killing a local woman and damaging dozens of houses. (Lanyon misses a trick here: the site of the derelict gasworks is now occupied by the gasometer-shaped Tate St Ives, as neat a bit of art/war coincidence as you could hope for.) By turning the handle on a blue-painted drum and looking through a visor, you can see a rickety recreation of what the Luftwaffe pilot might have seen that day. While on the subject of bombs, Lanyon then goes on to note that uranium from a St Ives tin mine was used in the Manhattan Project to develop the A-bomb (really?), before adding that, had Mondrian taken Ben Nicholson up on an invitation to join him in Cornwall for the duration of the war, local radioactive radon "would have knocked his verticals askew". "Maybe it is not the gods above but the minerals below that manipulate us," muses a wall chart, echoed in the book that accompanies the show.

You are about to yell "What bollocks!" when you realise that you are being played with, that harrumphing is exactly what Von Ribbentrop in St Ives wants you to do. This is not the history of art but a history through art; accuracy is gleefully sacrificed to imagination, what-was to what-if. Lanyon's is a story of possibility, not probability. If you wanted to categorise his work you might reach for "neo-surrealist". The what-the-butler-saw clunkiness of his vitrines, interspersed with the artist's own works on paper, have the child-like feel of Jannis Kounellis. Rather than furrowing your brow, you are asked to marvel, to giggle, to gasp at some of Lanyon's leaps of imagination, and snort at others. A jolly combination altogether.

Next Week:

Charles Darwent takes the high road to Edinburgh and the annual festival

Art Choice

Tempestuous lovers Frida Kahlo and Diego Rivera get a joint exhibition at Pallant House, Chichester, where their work is shown side-by-side for the first time in the UK, (till 2 Oct). Corrugated cardboard never looked so good; explore Michelangelo Pistoletto's maze-like swirls at the Sepentine Gallery, London (till 17 Sep).