David Sainsbury, made a minister in the Department of Trade and Industry by prime minister Tony Blair in April, created life peer Lord Sainsbury of Turville last year, and now chairman of the University for Industry's transition team, has been called too much of a thinker to run a supermarket chain.
Under his stewardship, as probably the last chairman to bear the Sainsbury name, the chain lost market leadership to Tesco and was forced to issue profit warnings. Correspondingly, his departure to work for Blair saw the share price shoot up.
With hobbies such as plant biology, cognitive neuroscience and art, had he not been called Sainsbury he would probably have been happier as a researcher or teacher.
He was born 58 years ago to Sir Robert Sainsbury and his wife, Liza, who was from a rich Dutch-Jewish margarine family. He was educated at Eton, which he hated, and King's College, Cambridge, where he swapped to psychology from history.
He joined the family firm in 1963 after studying for an MBA at Columbia University. He was appointed chairman in 1992, becoming the sixth Sainsbury to run the firm.
While there, he oversaw diversification into The United States and DIY but got into trouble for dismissing loyalty cards as "little more than electronic Green Shield stamps".
A philanthropist, he spends much of his estimated Pounds 3.3 billion personal fortune on scientific research and management education.
Part of the rest he spends on politics. He was a major backer of the ill-fated Social Democratic Party during the 1980s and now helps to fund the Labour Party.
He was listed among donors who gave Labour more than Pounds 5,000 last year - some said it was as much as Pounds 3 million.
He is described as "quiet, thoughtful and approachable" and with a kind of "innocence". He lives in West London and the Cotswolds with his wife, Susan, and three daughters.
They shop at Sainsbury's once a week.