Battle lines are drawn between the couple when Ian (Paul Bettany) has Margaret (Claire Foy) publicly banned from the castle she has devoted herself to. As Margaret scrambles to keep the details of her private life secret, she tries to convince her increasingly unwell father that she has nothing to hide.

But Ian seems to be one step ahead of Margaret at every turn, and by the time he offers her a deal - pay him off or face a humiliating divorce trail - a defeated Margaret is ready to go away quietly.

But when her beloved father dies Margaret has nothing more to lose. With the support of her only remaining ally, Peter, Margaret agrees to face trial and suffer the indignity.

But the consequences of her decision will be far greater and wider reaching than Margaret or anyone could ever imagine, and she’ll have to fight to prove that she is more than just a ‘Dirty Duchess'.

A Very British Scandal is made by Blueprint Pictures for BBC One and BBC iPlayer.