TAKE AN ARDENT young priest, a pretty woman and her ageing lover. Stir the imagination once and place the trio in eighteenth-century London on a warm April day when the lover, the libertine Earl of Sandwich, is fighting for his political life while his mistress, the mother of a brood of young Montays, goes to the theatre with a female friend. The priest, rightly or wrongly believing that she has rejected his offer of bliss in a country parsonage, tracks Martha Ray to the theatre and follows her into the crowded street. Here, later identified only as 'the man in black', he approaches her as she is climbing into a carriage, draws his pistol and blows out her brains, before firing with less accuracy at his own and being taken meekly off to Bridewell Prison where, it is subsequently reported, he passes an untroubled night.

Hackman, the priest (of whom nobody had heard until then), drew the biggest crowd for any execution in three years when, convicted of murder, he was hanged at Tyburn in 1779; when the corpse was dissected at Holborn, the capacity of the Surgeon's Hall proved insufficient for the eager spectators.