Following the audacious rescue of two Fenian leaders, during which a policeman was killed, the police arrested a number of suspects who were charged with murder. Some were acquitted, but three Irish members of the Irish Republican Brotherhood who lived in the area had taken part in the rescue.

William Allen, Michael Larkin and Michael O' Brien, were sentenced to death, earning them the epithet of 'the Manchester Martyrs'. Joseph O'Neill relates the sensational story of these men, their part in the rescue, their trial and the international reaction to their public execution.