Clan chief spotted a big future for student Obama

Mr MacNeil lived a rich and varied life, teaching around the world and writing many respected books.

But it was perhaps his role as The MacNeil of Barra, 46th chief of the MacNeil clan, that gave him most satisfaction.

Born in New York, he made several childhood visits to Scotland, and first visited Edinburgh around 1938.

He graduated from the universities of Vermont and Harvard, and met wife Nancy in 1951. She asked a university friend to find another male friend to make up the numbers of her group, and recalled: "He dug up Ian – and within 24 hours we were in love."

Active in the fight against McCarthyism in 1950s America, he was admitted to the New Hampshire Bar in 1956, subsequently holding various professorships at universities including Dar es Salaam and Harvard.

It was while at Harvard that he taught a young Barack Obama, and told Nancy that he thought he would be the first black US president.

She recalled: "My husband used to talk about his students all the time and this was a remark that he really seriously was making."

Mr MacNeil and Nancy moved to Edinburgh more than 20 years ago, when he was offered a visiting professorship at the University of Edinburgh.

On his retirement the couple were able to spend more time at their home in the Grange. He was an active member of the Cockburn Association, and particularly enjoyed the Capital's classical music scene.

He also kept a home on Barra, and was an active and popular proponent of the rights of islanders. In 2004 he transferred around 9,000 acres of his land, along with fishing and mineral rights, to the Scottish Ministers to be given to residents and arranged for Historic Scotland to run Kisimul castle at annual rental of 1 and a bottle of malt whisky.

His children, Roderick, 55, Jenny, 49, and Sandy, 45, said in a statement: "Our father was a fiercely independent thinker and a determined doer who believed deeply in the importance of human relationships.

"He applied his principles and his energy to the remarkably wide range of people and situations he encountered in a long and productive life.

"And he applied them to his children and grandchildren, in ways we are only beginning to appreciate. We are proud that he touched so many lives and privileged that he touched ours most of all."

Paying tribute to her husband, Nancy said, simply: "He was wonderful."