Nigella 'began affair with blessing'

Nigella Lawson began an affair with Charles Saatchi with the full blessing of her husband as he lay dying of throat cancer, a biography claims.

John Diamond 'realised the closeness of their friendship' and went as far as to suggest the couple should marry after his death, says author Gilly Smith.

There have long been rumours that Miss Lawson was seeing Mr Saatchi behind the back of journalist Mr Diamond - largely based on the fact that she moved in with him only nine months after her husband's death in 2001.

However, the biography out in September claims the television cook 'is too noble a person and has too much integrity' to have had an illicit affair while her husband was alive.

Though Miss Lawson herself did not give Miss Smith any one-to-one interviews, she did allow her access to interview her friends and family.

The book, titled Nigella Lawson, tells how Mr Saatchi, the advertising millionaire who owns Britain's largest private collection of modern art, became friendly with Mr Diamond in the late 1990s.

They often played Scrabble, particularly after Mr Diamond lost his voice during his four-year battle with cancer, which he famously wrote about in a newspaper column.

'John gave Nigella his blessing that she could, even should, marry Charles after he had died,' said Miss Smith. 'He realised the closeness of their friendship.'

Miss Lawson, 45, and Mr Saatchi, 62, married in 2003 and live in Belgravia with her children Cosima, 11, and Bruno, eight, from her marriage to Mr Diamond.

In interviews with Miss Smith, friends of Miss Lawson described how Saatchi gave her 'both physical and emotional comfort' during the final years of Mr Diamond's life. Miss Smith also says that Mr Diamond was the driving force behind his wife's career and many of the ideas in programmes such as Nigella Bites were his.