The British Fascist Party was comparatively insignificant until Mosley took over its leadership. Mosley was young, energetic, capable and an excellent speaker. Since I had met him in 1925 he had graduated from close friendship with MacDonald to a job in the second Labour Government; but he had become disgusted with the evasions over unemployment and had resigned to start a party of his own.

Unfortunately at the succeeding general election he fell ill with influenza and his party-in-embryo, deprived of his brilliant talents, was wiped out. Mosley was too ambitious to retire into obscurity. Looking around for a 'vehicle' he united himself to the British Fascists, rechristened 'the Blackshirts', and acquired almost automatically the encouragement of Britain's then biggest newspaper, the Daily Mail, which was more than willing to extend its admiration for the Italian original to the local imitation. That was a fateful influenza germ.

We have said a hundred times that if the life of Britain were threatened we would fight again, but I am not offering to fight in the quarrel of Jewish finance in a war from which Britain could withdraw at any moment she likes, with her Empire intact and her people safe. I am now concerned with only two simple facts. This war is no quarrel of the British people, this war is a quarrel of Jewish finance, so to our people I give myself for the winning of peace.

Mosley spoke effectively at great length. Delivery excellent, matter reckless. Interruptions began, but no dissenting voice got beyond half a dozen sentences before three or four bullies almost literally jumped on him, bashed him and lugged him out. Two such incidents happened near me. An honest looking blue-eyed student type rose and shouted indignantly "Hitler means war!" whereupon he was given the complete treatment.

In recent years, there has been an appalling TV biopic portraying Mosley as a heroic figure, their affair as one of history's great love stories, and fascism as a tremendous lark. Lady Diana was interviewed by Sue Lawley on Desert Island Discs and by James Naughtie on Today with a level of indulgent respect that neither of these interviewers would have summoned up for a working-class fascist. And four years ago, Jan Dalley's biography whitewashed Lady Diana and her husband.

Like Mosley's biographer Robert Skidelsky before her, Dalley fell for the central post-war Mosley lie: that anti-semitism was confined to his proletarian followers. She repeated uncritically the Mosley version that William Joyce, a leading fascist who broadcast for Hitler during the war, inspired fascist anti-semitism, and that Mosley was "unwise" to let Joyce edit his newspaper. But it was Mosley, not Joyce, who said during the Abyssinian war: "Greater even than the stink of oil is the stink of the Jew." It was Mosley who talked of German Jews as "the sweepings of continental ghettos hired by Jewish financiers". The only difference is: Mosley was rich and well-born; Joyce was proletarian and poor.

It was only after the second world war, when the Holocaust had so discredited anti-semitism that no politician could hope to benefit from it, that Mosley started to express well-bred distaste for his movement's wilder excesses, and to blame people like Joyce. By then Lady Diana was used to the idea that her wealth and social position would cushion her from the consequences of her views. During the war, hundreds of Mosleyites were interned without trial. But while humbler fascists were put in dank prisons and prison camps, and husbands and wives separated, the Mosleys were allocated a little house in the grounds of Holloway prison, where they hired other prisoners to wait on them.

They built barricades from paving stones, timber and overturned lorries. Women threw the contents of chamber pots on to the heads of policemen and children hurled marbles under their horses and burst bags of pepper in front of their noses.

Next Wednesday marks the 70th anniversary of the day that Jews, communists, trade unionists, Labour party members, Irish Catholic dockers and the people of the East End of London united in defiance of Sir Oswald Mosley's British Union of Fascists and refused to let them march through their streets.

Shouting the Spanish civil war slogan "No pasaran" - "They shall not pass" - more than 300,000 people turned back an army of Blackshirts. Their victory over racism and anti-Semitism on Sunday October 4 1936 became known as the Battle of Cable Street and encapsulated the British fight against a fascism that was stomping across Europe.

Mosley planned to send columns of thousands of goose-stepping men throughout the impoverished East End dressed in uniforms that mimicked those of Hitler's Nazis. His target was the large Jewish community.

The Jewish Board of Deputies advised Jews to stay away. The Jewish Chronicle warned: "Jews are urgently warned to keep away from the route of the Blackshirt march and from their meetings.

"Jews who, however innocently, become involved in any possible disorders will be actively helping anti-Semitism and Jew-baiting. Unless you want to help the Jew baiters, keep away."

The Jews did not keep away. Professor Bill Fishman, now 89, who was 15 on the day, was at Gardner's Corner in Aldgate, the entrance to the East End. "There was masses of marching people. Young people, old people, all shouting 'No Pasaran' and 'One two three four five - we want Mosley, dead or alive'," he said. "It was like a massive army gathering, coming from all the side streets. Mosley was supposed to arrive at lunchtime but the hours were passing and he hadn't come. Between 3pm and 3.30 we could see a big army of Blackshirts marching towards the confluence of Commercial Road and Whitechapel Road.

"I pushed myself forward and because I was 6ft I could see Mosley. They were surrounded by an even greater army of police. There was to be this great advance of the police force to get the fascists through. Suddenly, the horses' hooves were flying and the horses were falling down because the young kids were throwing marbles."

Thousands of policemen were sandwiched between the Blackshirts and the anti-fascists. The latter were well organised and through a mole learned that the chief of police had told Mosley that his passage into the East End could be made through Cable Street.

"I heard this loudspeaker say 'They are going to Cable Street'," said Prof Fishman. "Suddenly a barricade was erected there and they put an old lorry in the middle of the road and old mattresses. The people up the top of the flats, mainly Irish Catholic women, were throwing rubbish on to the police. We were all side by side. I was moved to tears to see bearded Jews and Irish Catholic dockers standing up to stop Mosley. I shall never forget that as long as I live, how working-class people could get together to oppose the evil of racism."

Max Levitas, now 91, was a message runner and had already been fined £10 in court for his anti-Mosley activities. Two years before Cable Street, the BUF had called a meeting in Hyde Park and in protest Mr Levitas whitewashed Nelson's column, calling people to the park to drown out the fascists. Mr Levitas went on to become a Communist councillor in Stepney.

"I feel proud that I played a major part in stopping Mosley. When we heard that the march was disbanded, there was a hue and cry and the flags were going wild. They did not pass. The chief of police decided that if the march had taken place there would be death on the road - and there would have been," he said.

"It was a victory for ordinary people against racism and anti-Semitism and it should be instilled in the minds of people today. The Battle of Cable Street is a history lesson for us all. People as people must get together and stop racism and anti-Semitism so people can lead an ordinary life and develop their own ideas and religions."

Beatty Orwell, 89, was scared and excited. "People were fighting and a friend of mine was thrown through a plate glass window."