LONDON (AP) — A British judge has exonerated three black men who served time in prison 50 years ago based upon the testimony of a corrupt police officer.

Judge Ian Burnett quashed the convictions of Winston Trew, Sterling Christie, both 69, and George Griffiths, 67, who were arrested after being swept up in a purse-snatching investigation.

The men were arrested in 1972 at the Oval Underground station, together with another man another man, Constantine "Omar" Boucher.

The group, dubbed the “Oval Four,” served eight months in prison but sought to clear their names. Boucher could not be located to take part in the case that was decided Thursday.

Christie's lawyer Steven Bird says it’s “a travesty” they waited 47 years to be exonerated. “Justice has now finally been done,” he said.