Mangrove Nine: the court challenge against police racism in Notting Hill

December marks the 40th anniversary of the start of Britain's most influential black power trial, itself a landmark event in the "irresistible rise of multiracial Britain".

In 1970, a group of black radicals were committed to stand trial on charges arising from violent clashes between the police during a protest march. From the outset, this was a political trial in which the police, Special Branch and the Home Office sought to discredit the leadership of the growing British black power movement. After 55 days at the Old Bailey, the Mangrove Nine were acquitted and forced the first judicial acknowledgment that there was "evidence of racial hatred" in the Metropolitan police.

The nine's campaign was part of a campaign to defend Notting Hill's black community from police racism. At the end of the 1960s, Frank Crichlow's Mangrove restaurant became the beating heart of the area's West Indian community. At the same time, "the heavy mob", a group of officers who patrolled the community like a colonial army, began a campaign to close the Mangrove, raiding the restaurant 12 times between January 1969 and July 1970. The police stuck to the story that the Mangrove was a drugs den, despite the fact that their repeated raids yielded not a shred of evidence.

Darcus Howe, who worked at the Mangrove, urged Crichlow to look to the community for support. Together with the Black Panther Movement, they organised a demonstration. On 9 August 1970, 150 protesters marched to local police stations demanding the police get their "hands off the Mangrove". Police preparation for the march was extensive. More than 700 officers were available. Special Branch's "black power desk" was also mobilised to monitor the protest. Heavy-handed policing prompted violence and the authorities started to build a case against the demonstration's leaders. Home Office documents reveal this was a deliberate strategy to target and decapitate the emerging black power movement.

Senior civil servants discussed a variety of legal options in their reports to Reginald Maudling, the then Conservative home secretary, before settling on this approach. They could accuse the protesters of inciting racial hatred under the Race Relations Act, a tactic which had succeeded in the past. But this strategy was discounted for fear of turning the defendants into martyrs. Another possibility was to use the provisions of the Conservatives' 1970 Immigration Act to deport Crichlow and other known black radicals. However, Crichlow's residency in the UK since the early 1950s ruled this option out. Finally, the director of public prosecutions proceeded with the charge of incitement to riot.

The presiding magistrate viewed the case for what it was, and ruled that parts of the statements of 12 officers were inadmissible, as they clearly equated black radicalism with criminal intent. As a result, the judge threw out the charges of incitement. However, the authorities were not willing to admit defeat. The DPP took the unusual step of reinstating the incitement to riot charges and the defendants were rearrested in a series of dawn raids.

The nine decided on a radical legal strategy. Darcus Howe and Althea Jones Lecointe would defend themselves and in so doing expose the political nature of the trial and the brutality of policing in Notting Hill. Barbara Beese, another member of the nine, approached the radical barrister Ian McDonald who agreed to represent her and to perform the crucial role of mediating between the defendants who were defending themselves, and the barristers acting for the other defendants, to prevent any divisions.

The second part of their radical strategy was to demand an all-black jury. Howe, who had studied law, grounded this demand in the right to be tried by a jury of peers. Thus, Howe appealed to ancient rights enshrined in Magna Carta in the same way that the American Panthers cited the 14th Amendment as the constitutional basis of its call for black defendants to be tried by black juries.

McDonald's application for an all-black jury lasted for two days. He cited old cases that allowed Welsh marchers to have a Welsh jury, Italian merchants to be tried by a jury of "the half-tongue", or half-Italian. McDonald pointed out that the established practice for centuries thereafter had been to select the jury from the neighbourhood of the accused. The judge, a man who was known for his distaste for political radicalism, dismissed the application out of hand.

The defendants were prepared for this turn of events, and Howe and Lecointe-Jones began to vet potential jurors politically, asking them what they understood by terms "black power" and which newspapers they read. Again the judge intervened to stop this line of questioning. Nonetheless, the defence dismissed a total of 63 jurors, each defendant using their right to dismiss seven potential jurors. In so doing they ensured that two of the 12 jurors were black and, perhaps more importantly, stamped their authority on the proceedings.

Police witnesses justified their actions by labelling the Mangrove restaurant "a haunt of criminals, prostitutes and ponces". The turning point came as Howe exposed problems with the police testimony and a police officer was ordered to leave the courtroom when he was seen signalling to other prosecution witnesses as they gave evidence.

In his closing submissions, McDonald reminded the jury that "this is not the court of star chamber. This is not Russia." Nor, he continued, was it the US where a Chicago judge had recently ordered Bobby Seale, co-founder of the Black Panthers, to be bound and gagged in the dock to stop him speaking out. Despite this, MacDonald claimed that Judge Clarke had sought to subject the defendants to a form of "naked judicial tyranny".

In his closing speech, prosecuting counsel Michael Hill said the issue was whether the jury accepted the evidence of police witnesses alleging a conspiracy by the nine to incite a riot.

Finally, the nine's legal strategy triumphed: the jury believed the defendants rather than the police. All nine were acquitted of the principle charge of incitement to riot, while five of the nine, including Darcus Howe and Frank Crichlow, were acquitted of all other charges. Summing up, the judge concluded that the trial had "regrettably shown evidence of racial hatred on both sides".

The judges' words were electrifying. Horrified, the Met's assistant commissioner wrote to the DPP seeking a retraction of the judge's statement. The statement was never withdrawn.

The lessons of the trial were not lost on the government who moved to "modernise" the justice system by restricting the rights of future defendants seeking to influence jury selection. Nonetheless, the Mangrove Nine had turned the fight against police racism into a cause celebre. Across the country activists who had been caught up in the campaign were inspired, for the nine had shown that it was possible to take on the authorities in the name of racial justice and win.

Dr Robin Bunce is a director of studies for politics at Cambridge University and Paul Field is a lawyer, writer and human rights activist. They are co-writing a biography of political activist Darcus Howe