Our Great British Houses series continues with another gem of The National Trust’s collection. About 10 miles from the centre of London is one of the most magnificent houses of Stuart England, Ham House. This lavish mansion is a treasure trove of 17th century art and architecture, a dazzling red-brick jewel on the muddy banks of the River Thames.

But Ham House also has a remarkable history of espionage and secrets. During the tumultuous years of the English Civil War, the Commonwealth and the Restoration, Ham House lay at the heart of political conflict. In this documentary Alice Loxton discovers how the Murray family - led by a remarkable mother-daughter team of Catherine and Elizabeth Murray - survived this troublesome period. Despite being fiercely loyal to the crown - even ferrying secret letters to the exiled Charles II - the Murray’s also maintained a friendship with the Cromwell family. It was an audacious act of bravery, resilience and espionage.