Deborah Dowager Duchess of Devonshire has died aged 94.
Her son, the Duke of Devonshire, announced the death in a statement from Chatsworth House, her stately home.
The 12th Duke said in a statement: “It is with great sadness that I have to inform you that Deborah Dowager Duchess of Devonshire passed away peacefully this morning.”
An announcement about funeral arrangements will be made shortly.
The Duchess was the last of the famous Mitford sisters whose activity fascinated - and sometimes scandalised - British society in the 1940s.
One of her sisters, Unity, was a friend of Hitler and another, Diana, the second wife of British fascist leader Sir Oswald Mosley.
But Deborah was more focused on her home life. Nicknamed the ‘housewife duchess’, she made Chatsworth one of the most successful and profitable stately homes in England.
The model farm on the Chatsworth estate was conceived by her 40 years ago as an education centre for children and parents alike. It was one of the first sites of its kind to open up as a learning resource to teach children about food, animals and agriculture.