On a biting cold morning on November 28, 1972, a Frenchman was guillotined for a murder he did not commit, in a case that so traumatised his lawyer he would spend the rest of his life campaigning to end the death penalty.

Roger Bontems, 36, was beheaded for being an accessory to the brutal murder of a nurse and a guard during a break-out attempt at a prison in eastern France.