"OH, there's Unity's swastika, " says Neil MacGillivary casually, as a red armband with the Nazi symbol picked out in black thread falls from between the pages of a photo album.

MacGillivary, now 90 years old, is probably the last surviving link to a remarkable tale of a notorious Nazi sympathiser and close friend of Hitler who lived out her final years on a tiny island off the west coast of Scotland.

The little-known story of Unity Mitford's final years on Inch Kenneth, one of a sprinkling of isles off Mull's west coast, is about to be aired in a new book, The Broken Lyre, by broadcaster and historian Lorn Macintyre.

Unity Valkyrie Mitford was born in 1914, the fourth daughter of Lord and Lady Redesford and sister of Diana Mitford, who wed the British fascist leader Sir Oswald Mosley.

Her other sisters included Jessica, or Decca, Mitford who became an author and a lifelong communist, and Nancy, a novelist and biographer.

Unity became besotted with Hitler and fascism, learned fluent German and greeted everyone with the Nazi salute "Heil Hitler".

She was so infatuated with the Fuhrer that she travelled to Munich in 1933, determined to meet him. She not only achieved her goal but became part of the Nazi elite circle, meeting Goering, Himmler and Goebbels, and accompanied them to meetings, rallies and the Berlin Olympic Games.

She was part of an international set that raced enthusiastically to Vienna to witness the Anschluss of March 1938, when Hitler annexed Austria in the first stage of his plans to create a Third Reich.

Hitler told newspapers in Germany that Unity was "a perfect specimen of Aryan womanhood". She was given the gold Nazi party badge, the highest honour Hitler could bestow. Such was their mutual admiration that the Daily Telegraph even reported - wrongly - that Unity and Hitler were engaged to be married.

However, when war came, Unity's loyalties were so torn that she shot herself in the head. She survived and Hitler personally paid for her to receive the best medical treatment before she was sent back to England in 1940, still with a bullet in her brain.

About this time Lord Redesford bought Inch Kenneth for Unity and her mother, but she was not allowed to travel there until 1944 since Mull was an assembly stage for Royal Navy corvettes. "The British government thought she was a very dangerous woman, " said Macintyre. "On Mull she was just accepted as a poor soul."

Stories persist of Unity signalling late at night with a bicycle lamp for German U-boats that never came.

Unity kept copies of the antiSemitic paper, Der Sturmer, and had an autographed copy of Hitler's autobiography Mein Kampf. "To the very end, she never accepted that Hitler caused the Holocaust. She could never believe anything about Hitler except good, " Macintyre adds.

Unity, still suffering the effects of her head wound, lived a simple life on Inch Kenneth. There was a little hut on the shore where she would wait to be taken by boat across to Mull for occasional dances.

It was at one of these dances that Neil MacGillivary encountered her.

"I once took Unity to a little dance in the school house at Gribun [on the mainland of Mull]. I'm the only man alive today that's danced with Unity Mitford, " he recalls, chuckling.

"She was a big strapping woman. She says to me, 'I think you Scottish people are frightfully lucky being able to wear the kilt and dance'."

Sitting in the front room of his house by the peaceful shores of Loch Scridain, a short car ride away from Gribun, MacGillivary says the bullet "affected her brain" so that she would be "at all kind of silly things". One time she set about making a cake by breaking four or five dozen eggs but adding no flour - an outrage at the end of the war when eggs were rationed. But the people of Mull didn't judge Unity.

"She was just made welcome among the local people. There was no animosity toward her at all, " says MacGillivray.

In 1948, Unity suffered cerebral swelling around the lodged bullet and developed meningitis. She was taken to hospital in Oban but died shortly afterwards.

"The doctors gave her 10 years to live and she died within two weeks of the 10 years, " MacGillivary says.

He went on to spend 13 years working for Lady Redesford as general manager and boatman on Inch Kenneth, while his wife looked after the house. His children were brought up there. "They were the happiest years of our married life, " he says.

Lady Redesford never talked about Unity again. She would spend winters in London and summers on Inch Kenneth, where she would receive picnic guests, such as Rab Butler, the Conservative Cabinet minister who served under Churchill.

Members of the Mitford family would also come up. MacGillivary remembers Lady Mosley as "a lovely lady".

"It must have been a great house when they all got together: communists, fascists and conservatives."

Lady Redesford died on Inch Kenneth. "I was supposed to die at the same time. She kept saying, 'I can't go without you'.

But I didn't oblige her, " adds MacGillivary.

Michael Blakenham, who lives on Little Colonsay and recently helped launch a bid to secure Unesco World Heritage status for the Staffa Archipelago, including Inch Kenneth, was aware of the Mitford story, another element of the patchwork of curiosities that make up the "remarkable area".

"There are all sorts of interesting stories here, " he added.

The Black Lyre by Lorn Macintyre is published by Black Ace Books in the autumn