The train had been stopped because of reports of a fight with white youths. At that point, two white girls, aged 21 and 17, alleged that they had been raped. Victoria Price, the older girl, maintained her account through a long series of trials right up to her deathbed. Ruby Bates dramatically withdrew her accusation when the series of retrials were shifted to a quieter rural court in Alabama than Scottsboro had been. By now the United States Supreme Court had intervened for the first time, reversing convictions after inadequate representation.

Back to Ruby. Called as a dramatic late defence witness by the brilliant New York attorney Samuel Leibowitz, now overseeing the defences, she said that nothing at all had happened. Asked why she had lied, she said it was because Victoria had told her that they might have to stay in jail if they did not frame up a story after crossing a state line with men.

In a later trial, in a sworn deposition made in a New York hospital, Ruby repeated that neither of them had been raped. The medical evidence had shown traces of semen, but none of the signs of violence which might have been present after a prolonged multiple rape. Both girls at different times accepted they had had intercourse in the relevant period before the incident. Later, another examining doctor confided to Judge Horton, one of the heroes in this story, that they had not been raped and he had laughed when he examined them.

But that is a global picture in retrospect. For all of the defendants were convicted, together and separately, and sentenced to death by electric chair, save the youngest. Ultimately after a litany of trials and retrials, all were retrieved or pardoned but not before one had died in custody and another shot in the head in a violent incident. That is a very short summary of one of the most controversial and seminal episodes in American legal history.

It overlays fundamental issues of crude justice, fear, all white jurors until the Supreme Court intervened again, and prolonged racial prejudice. It was brought stunningly to life in one of the most brilliant theatre productions I have ever seen. I was lucky enough to catch it on its second night at the Young Vic when we rose as one to give it a prolonged standing ovation. Much the same thing has happened at the Garrick, where it later transferred, winning prestigious theatre awards in the process. This time, in a performance partly for English lawyers, I was entranced again. Perhaps it was a fraction less exuberant than I remembered, but the stunning ending was even more shocking: Rosa Parks refusing to give up her seat to a white passenger in a bus ride which ultimately changed history and many minds.

But how could a musical do justice to such a story? As one of its creators said at the outset, it had to be entertaining. This was the brainchild of Kandor and Ebb, creators of Cabaret, book by David Thompson with the inspiration of the brilliant director and choreographer, Susan Stroman. They hit on the idea of turning the stylised form of an old style minstrel show completely on its head. Such entertainment would have an interlocutor at the centre of a semi-circle, with two musicians and entertainers (Mr Tambo and Mr Bones) on the side, intervening in the musical performances by white performers blacked out for the purpose. Here they would keep the white interlocutor but all other performance would be black actors, playing white and black personalities in the story.

So imagine an intensely attractive musical score and dancing of the highest energy and quality and a tremendous cast. Then allow the actors to rearrange the very simple furniture to turn, for example, chairs into a terrifyingly minute cell or solitary confinement. Capture key moments in a very convoluted story in song and dance and gradually bring out the chill of injustice. So clever and so effective. Afterwards Susan Stroman herself took us very fluently through the history of the production. Some of the most shocking lines in one song had come straight from a trial transcript.

Now after an original off Broadway production, there is the possibility of it being staged throughout all America and the world. It will take courage still for it to resound in parts of the South. But it is significant that, as a direct result of this production, in November 2013, the Alabama Board of Pardons granted posthumous pardons to the three Scottsboro boys still denied justice. Governor Robert Bentley in a statement said that day the Scottsboro boys had finally received justice.

Above all, I want to praise to the skies both individual performances and stunning ensemble. The lead defendant, Haywood Patterson, was played by Brandon Victor Dixon, who created the role in 2010.

I cannot imagine a better performance. Both Mr Tambo and Mr Bones were superb. The largely silent Dawn Hope was an evocative presence throughout until her Rosa Parks moment and Julian Glover captured powerfully the benevolent oversight of proceedings, with the sudden aggression necessary in brief moments. I left feeling that I had been privileged to be present at an evening of undiluted theatrical excellence.

Unforgettable. It will be revived again and again and will inspire generations of theatregoers indefinitely.