Late one night in December 1671, a band of soldiers fell upon a man outside his London lodgings. He was ambushed returning from a late supper. Having beaten and pinned him to the ground, the troopers made a point of disfiguring him – slitting his nose – before neighbours and passers-by drove them away. The victim, Sir John Coventry, was an MP. Shortly before the incident, he had made an unwise, if well-received, joke in the Commons about the salacious tendencies of Charles II. The king, it seemed, made his feelings on the matter clear in the street.

The incident was recorded angrily by Andrew Marvell, a fellow MP and a hard-working campaigner for religious reform and toleration. To Marvell – as to us now – the affair encapsulated all that was wrong and dark