The march of 22 November 1910 cannot be understood without the march of 18 November. On that earlier Friday, the suffragettes had attempted to deliver a petition to Parliament after Asquith had announced he would not give time to the Conciliation Bill. They were met by Metropolitan Police officers who, according to subsequent investigations and the testimony of the women themselves, deployed sustained physical and in some cases sexual violence over the course of six hours. It became known as Black Friday. Two women would later die of injuries sustained that day. Four days later, when Asquith offered his hedged response in the Commons, the women of the Women's Social and Political Union had already made their decision. They were not going to petition again. They were going to Downing Street.

The Cabinet was meeting that afternoon. Two hundred suffragettes marched into the heart of government, smashing windows at the Colonial Office and the Home Office as they went. Stones broke the windows of Asquith's own car. Around twenty women approached Number 10 itself from the back, slipping between the buildings, and found themselves face to face with Augustine Birrell, the Chief Secretary for Ireland, who was hurrying to the Cabinet meeting. "They pulled me about and hustled me," he later complained. They "stroked my face and knocked off my hat." Trying to escape, he twisted his knee badly and dislocated his kneecap. He spent the next weeks limping. The arrests began. Emmeline Pankhurst was taken away; so was her younger sister, Mary Clarke. Another 157 women and three men were charged. Mary Clarke had thrown a stone through the window of Canon Row Police Station because they would not let her see her sister, who was being held there.

Birrell was an interesting figure in this story, and his reaction tells us something about the texture of Edwardian politics. He was a literary man, a Liberal, a friend of George Bernard Shaw. He had no real appetite for prosecuting the women who had ambushed him on the way to a Cabinet meeting. On 21 February 1911, he wrote to the Home Secretary, Winston Churchill: "Let the matter drop but keep your eye on the hags in question." The note has the casual cruelty of its era — the word "hags" applied to women who had committed political offences out of political conviction — and also the strange forbearance of a Minister who declined to send his attackers to prison. Both qualities coexisted in the response to suffragette militancy. The state could not quite make up its mind whether these women were criminals, lunatics, or political prisoners. It treated them, by turns, as all three.

Mary Clarke would die a few weeks later, on Christmas Day 1910, after being released from Holloway Prison. Her family blamed her death on the violence she had endured during the Black Friday march and the force-feeding she had been subjected to in prison. Emmeline would call her sister the first martyr of the cause. The Conciliation Bill failed. So did its successors. The vote on equal terms with men did not arrive until 1928, eighteen years after the Battle of Downing Street. By then, most of the women who had marched on Number 10 that November afternoon were in middle or old age, and a generation of younger women had grown up in a world where Black Friday and the broken windows on Whitehall were stories told by aunts and grandmothers. The brass plaque outside Number 10 has not changed in over a century. But the women who can now walk past it as Prime Minister, Cabinet Secretary, or simply as voters do so because of an afternoon in 1910 when two hundred of their predecessors decided that polite petitioning had become an absurd mockery of a pledge.