Charles Darwent on Schwitters in Britain: Sweet wrappers that made fascists quail

Kurt Schwitters, the German one-man avant-garde, was neglected in his adopted Britain but did the spadework for generations of artists

The Tate's new show sounds like a send-up. What would the madcap Merzman be doing here in the Lake District for seven years?

On 19 June 1940, the artist Kurt Schwitters stepped off an ice-breaker and on to the quay at Leith. For the previous three years he had lived in Norway, in flight from the Nazis.

Born in Hanover in 1887, Schwitters had, in 1919, tried to join the Berlin chapter of Dada – the anarchic anti-art movement born of the Great War – and been turned down as an Expressionist. Not one to take no for an answer, his response was a one-man movement called Merz, the name lifted from a piece of paper stamped Commerz und Privatbank, which Schwitters had put in a collage, or Merzbild (Merz-picture). Over the next two decades, the garrulous German became a key figure in the Continental avant garde, flirting with De Stijl and Constructivism, joining the Paris group Abstraction-Création.

Two decades before Homo Ludens, Schwitters was Johan Huizinga's playful man. One of his earliest pieces, Merzbild 46A. Das Kegelbild, takes the form of a skittle-board. They are games of intent, though, their visual puns exposing a society that is at heart absurd. Like a big kid, Schwitters kicks over our social sandcastles. One collage, Mz. 307, bears a bus ticket stamped "Erwachsene 1 Platz" – one adult seat. Adulthood was never for him.

And then, in 1937, came Entartete Kunst, and Schwitters's unruly mind-games fell foul of the Nazis. When Goebbels' exhibition of Degenerate Art opened in Munich in July 1937, it contained four Merz works. Earlier that year, their maker had joined his son, Ernst, in exile near Oslo. Three years after that, with the Germans in Norway, Schwitters boarded the boat to Leith.

So how is it that this comes as news to most people? When Schwitters died in January 1948, he had been in Britain for nearly eight years. In love with the place, and with an English woman he nicknamed "Wantee" for her endless cuppas, he had applied for British citizenship: it came through on the day he died. His last great work – the fourth in a series of live-in sculptures called Merzbau, or Merz constructions – was installed in a barn in Ambleside. And yet the idea of Kurt Schwitters as an artist in Britain still seems odd.

For this we have to thank the same native insularity that has made us forget the British period of other giants of the Continental avant garde: Piet Mondrian, Naum Gabo, László Moholy-Nagy and John Heartfield, who all moved here in the 1930s. The critic Raymond Mortimer put it well, reviewing a show called Twentieth Century German Art held in Mayfair in 1938 as a riposte to Entartete Kunst, (the Nazis' "degenerate art"), and in which Schwitters had two works. Hitler was reported to have been infuriated by the London show. "[Britons] who go to it are only too likely to say, 'If Hitler doesn't like these pictures, then it's the best thing I've heard about Hitler,'" Mortimer wrote.

So Schwitters in Britain is various things: a much-needed attempt to write its subject back into English art history; a cleverly curated bringing-together of the work Schwitters made while he was here; and a gentle massaging of the facts.

There is no doubt that Schwitters found the English and their language stimulating. His magpie eye finds treasures everywhere, and they are specifically local treasures. A collage called Bassett includes the wrapper from a brand of licorice allsorts. Another work – sweets were rationed – bears a scrap of paper with the legend "[choc]olate [pep]permint".

These strange part-words, freed from meaning, become like runes. And even his humour seems to take on a self-deprecating English cast. The wrapper of the last-mentioned work, En Morn, sits over a headline cut from a newspaper. It reads, "These are the things we are fighting for".

And yet Mortimer's prediction was correct. Although this show emphasises Schwitters' links with the British avant garde, in truth they were sparse. Artists such as Ben Nicholson and Barbara Hepworth were too busy struggling themselves to bother with a nutty German. Letters to Kenneth Clark, in whose gift lay official war art commissions, bore no fruit. Nor did attempts to reach an audience for Merzbilden: one of the most poignant objects in this show is a rejection slip from the 1941 Royal Academy Summer Exhibition.

To make ends meet, Schwitters painted the portraits of Cumbrian worthies – £1 for a bust, a guinea with hands. A decade after his malnourished death, his work was discovered by Richard Hamilton and Eduardo Paolozzi. Without the Merzman there would have been no Pop Art, and so no Emin or Rauschenberg. It's a sad story, but one that needs to be told.

To 12 May (020-7887 8888)

Critic's choice

Woo! It's Juergen Teller. That's not just a whoop of excitement, it is also the name of the exhibition by the German photographer at the ICA in London – but it's apt for this startling, sexy show, which features plenty of fashion names, actresses and rock stars (till 17 Mar). There is photography on show at Tate St Ives too, drawn from the 30-year career of Peter Fraser, who turns his lens on found objects (till 6 May).