In September 1656, Oliver Cromwell’s agents arrested an Old Bailey apothecary called Anthony Hinton. They suspected him of working for the Sealed Knot, an underground royalist organisation, which was plotting to murder Cromwell and restore the monarchy. And they were right. Under interrogation, Hinton admitted to carrying letters for royalist spies, among them Susan Hyde, the sister of the future Charles II’s chief adviser Sir Edward Hyde.

Susan’s fate was sealed. One Sunday morning a few weeks later, three men burst into her bedroom. Arrested and taken by coach to London, she was patently terrified. When she reached the capital, her interrogators were so intimidating that she “fell into...a trembling [and]was not able to speak”.

Cromwell’s men ripped her clothes off and threatened her further,