See: ‘Oval Four’ men jailed in 1972 cleared by court of appeal in London (Guardian, link):
“Three men who were convicted nearly 50 years ago on the evidence of a corrupt police officer have finally had their names cleared by senior judges.
Upholding an appeal against conviction by Winston Trew, Sterling Christie and George Griffiths – who, with Constantine Boucher, were part of the “Oval Four” – the lord chief justice, Lord Burnett, told them: “Our regret is that it has taken so long for this injustice to be remedied.”
The men were arrested in March 1972 by a group of undercover police officers at Oval Underground station and accused of “nicking handbags” on the tube. They were beaten in the police cells and then charged with attempting to steal, theft, and assault of the police.”