By the time the Nazi party came to prominence by winning 107 seats (18.3% of the votes) in the Reichstag election of September 14 1930, British newspapers could not ignore Hitler and his movement. But, as Brigitte Granzow showed long ago in her book, A mirror of Nazism, the reportage was replete with distortions and misinterpretation.

In an article on September 21 that year, the Observer echoed the widely held belief on the left that Hitler was the creature of big capital. It saw the real dangerman not as Hitler, but as the media tycoon and leader of the German National People's party, Alfred Hugenberg. The "Hugenberg manoeuvres", it stated, had aimed to promote both Communists and Nazis as a vehicle to weaken the organised working classes. "Hugenberg, and not Hitler, will ultimately call the Nazi tune."

A week later, the newspaper dismissed Hitler as "dramatic, violent and shallow", and "a lightweight", seeing him as "not a man, but a megaphone" of the prevailing discontent, fronting a militarist reaction, which would mean the destruction of peace. The newspaper went on to claim, remarkably, that Hitler was "definitely Christian in his ideals", and, even more strangely, that these matched the ideals of German Catholics.

The Guardian thought on September 25 1930 that the exclusion of the Nazi party from Reich government, given its electoral success, was not in the best interests of German democracy and that their involvement would "in the long run ... help to perpetuate this democracy".

On the very day that these views were published, Hitler told a court in Leipzig (where three young army officers with Nazi sympathies were on trial for preparing to commit high treason) that his movement would come to power legally, but that it would then shape the state as its members wanted it, and that "heads would roll".

The Guardian maintained its view, however, that Hitler, "while full of the verbiage of revolution", was "no revolutionary leader". It claimed that he lacked courage, and that his baleful threats before the Leipzig court raised unnecessary fears, while his assurances of proceeding legally had hardly been noticed. It dismissed him on September 29 1930 as "the ranting clown who bangs the drum outside the National Socialist circus". Few things, the newspaper had remarked three days earlier, were less likely than that Hitler would gain sole power in Germany.

By 1932, as the crisis of German democracy deepened, British newspapers devoted far more attention to Nazism. Even now, however, underestimation of Hitler was commonplace. The Observer, still on February 21 1932 seeing Hitler as no more than a demagogue propped up by financially powerful nationalists, reversed course following his candidacy for the Reich presidency in March, when it wrote (March 20 1932) that it would be wrong to regard him "as a mere agitator and rank outsider". Here, as in the Guardian (which still implied on March 30 1932 that Hitler was no more than a charlatan), the emerging view was that he was a "moderate", who might possibly develop into a statesman, but could not control his own violent and unruly movement.

This related also to anti-semitism. The Observer, in its article on March 20 1932, hinted that attacks on Hitler's anti-semitism exaggerated the danger, adding: "It must not be forgotten that the major part of the German Republican Press is in Jewish hands."

As the political violence intensified during the summer and autumn of 1932, the Guardian persisted in its belief that Hitler was being outflanked by the more radical sections of his movement.

In its article headed Hitler Losing Control on August 10 1932, Joseph Goebbels, the party's propaganda leader, was seen as the real radical spearhead of the Nazi aggression. On August 16, after Reich president Hindenburg had refused three days earlier to hand the chancellorship to Hitler, the newspaper claimed Hitler had never been the "real master" of the Nazi movement, which had pressed him into demanding that he should be "Germany's Mussolini against his own better judgment".

When Hitler overcame the crisis within the Nazi movement in early December 1932 about the party's strategy, leading to the resignation of one of his chief lieutenants, Gregor Strasser, the Guardian on December 10 curiously interpreted the episode as a victory for Goebbels and the party radicals.

Consistently playing down Hitler's importance and viewing him as a reactionary inevitably meant that the final machinations that brought him to power on January 30 1933 were seen as the "victory" of the reactionary forces of German nationalism. Nevertheless, the next day the Guardian did prophetically comment that "it is by no means certain that the Nazis will be the 'prisoners' of the Nationalists in this new Government", and that Hitler's appointment as Reich chancellor was "an hour which may prove a turning-point in the history of post-war Germany".

· Sir Ian Kershaw is professor of modern history (modern German history) at the University of Sheffield