The Guildford Four and the Maguire Seven did not carry out the bombings – but who really did remains a mystery to this day.
The Guildford and Woolwich bombings were the work of the Provisional IRA . Of that there was never any doubt.
But republican leaders who shouted ‘miscarriage of justice’ and campaigned to get Gerry Conlon, Annie Maguire and company out of jail were never going to offer up any alternative names.
After the Guildford Four and Maguire Seven were cleared no one else was ever charged with the crimes for which they wrongly spent years behind bars.
It is the same story in Northern Ireland where many hundreds of terrorist murders remain unsolved.
However, the cases of the 11 wrong convictions – and those convicted and later cleared of the Birmingham bombing – sent shockwaves through the British policing and judicial systems. They were described as the worst miscarriages of justice in history.
There were investigations and inquiries into what went wrong, but no terror charges.
Avon and Somerset Police carried out a review of the Surrey force investigation and was highly critical in its findings.
Eventually the only charges in relation to the Guildford bombings were against three Surrey detectives involved in the investigation who were charged with conspiracy to pervert the course of justice.
By the time they went to trial in 1993 all three had retired from the force.
In May 1993, a jury of six men and six women took more than eight hours to clear the ex-officers of the charge of fabricating notes of interviews with Paddy Armstrong, one of the Guildford Four.
Labour MP Chris Mullin, now a British Foreign Office minister, campaigned for the release of the Guildford Four.
At the end of the police officers’ trial he said he regretted that it had been “primarily concerned” with the retrial of the Guildford Four, and that it had been done without any of the original defendants being given the opportunity to respond.
The acquittal of the retired detectives meant, he said, that the question of how Mr Armstrong and others were persuaded to confess to a crime they did not commit would remain a “mystery which students of British criminal justice will continue to ponder”.