'You're like Inspector Clouseau, vulgar, wrong. A fantasist obsessed with sex'. 'Bloody nonsense. Grow up'

An unusually bitter dispute has broken out betweenthe family of Graham Greene and Norman Sherry, the man he entrusted to write the definitive account of his life.

An unusually bitter dispute has broken out betweenthe family of Graham Greene and Norman Sherry, the man he entrusted to write the definitive account of his life.

Relatives have been angered that Professor Sherry, whose third and final volume of Greene's official biography will be published this week, dwells extensively on the writer's sexual conquests at the expense of his literary career. They say they are "deeply embarrassed" by such a "poor" book and accuse Sherry of a "fixation on sex".

Moreover, they consider the book "vulgar", "extremely dull" and a "total misrepresentation" of Greene. They even liken Sherry to the bumbling detective Inspector Clouseau, who "doesn't understand anything".

The response in this war of words, and for once the phrase is justified, is equally blunt. Sherry, a British professor of literature who has spent 27 years working on the three volumes, yesterday described the family's claims as "bloody nonsense" and defended his "even-handed account, full of the truth". He said he was hurt and shocked by the family's reaction.

Greene won worldwide admiration for a series of novels such as Our Man in Havana, The Quiet American, Brighton Rock and The End of the Affair. Yesterday the centenary of his birth was celebrated at his old school in Berkhamsted in Hertfordshire with writers such as David Lodge and Sir John Mortimer fulsome in their praise.

But his convoluted personal life was as gripping as any of his fiction. He conducted a series of affairs, including one with Catherine Walston, who was married to MP Harry Walston, and whom Sherry calls "the greatest passion of his life". The book chronicles how he once compiled a list of 47 prostitutes he had slept with, and Sherry describes Greene as a "sexual raider".

In edited extracts from Sherry's book serialised by another newspaper, he relates how, when travelling in China in 1957, Greene told officials: "There are two things I want - a pretty girl to sleep with and to know where I can get some opium." But the emphasis on his sex life has riled his family. Amanda Saunders, Greene's niece and personal assistant for many years, said: "The family are deeply embarrassed to be associated with a biography as poor as this.

"[It] is an absurd distraction from Graham's work. It is an utter misrepresentation. Norman does Graham a great disservice with his obsession with gossip ... disappointing in someone who professes to be an academic, and a dereliction of Norman Sherry's duty as a biographer. The biography is not only vulgar and poorly written but extremely dull. Norman Sherry is very like Inspector Clouseau. He doesn't understand anything, he gets many things wrong - he is a fantasist."

She said her view was shared by Greene's son Francis. Another niece, Louise Dennys, who was also Greene's publisher, said Sherry wrote his book without any reference to the detailed correspondence she had had with her uncle over 12 years.

"It seems a shame that a biography that does claim to look at the working and personal life through to the end doesn't take the opportunity to look at that particular aspect." Greene's daughter Caroline Bourget, attending the centenary celebration yesterday, was also dismissive of the book, saying: "We're not happy about it."

She claimed Greene was "starting to regret" the appointment of Sherry as his official biographer by the time he died. "He's just put pages and pages of Graham's writing and some fairly banal comment. I don't think it's a biography as such."

Christopher Hawtrey, a Greene scholar, said many illuminating episodes in his literary career were missing from the biography. These include a failed attempt to stage Brighton Rock as a musical in the 1960s, and an extended correspondence he conducted with the science fiction writer Ray Bradbury about Catholicism and writing in general.

He claimed the biography was dominated by the relationship with Catherine Walston which had peaked at the start of the period covered by the final volume, 1955 to 1991. Greene spent the 32 years up to his death with another lover, Yvonne Cloetta.

Cloetta had helped with Sherry's research for the first volume but she was so dissatisfied with the results that she wrote to him saying: "You have betrayed me. You have betrayed Graham and you have betrayed your craft." They had no further contact.

Sherry, 69, said he was "hurt" by the family's criticisms of his biography, but rebutted the suggestion he was obsessed by sex as "bloody nonsense".

The professor claims that Amanda Saunders saw the book in advance and raised no significant objections with him at the time. "I'm not the man who's slept with 47 prostitutes ...I wish I could have been as sexy as Graham Greene. Alas I wasn't, what can I say? If they think the only thing I wrote about Greene was about sex, how in hell did I write three volumes?

"I am shocked by their comments. Anyone who reads the third and final volume will know it is an even-handed account full of the truth."

Sherry, who is professor of literature at Trinity University in San Antonio, Texas, and who was asked to write the biography after first meeting Greene in 1974, added: "I worked 27 years doing [Greene] justice, and I am positive he would shake my hand here at the end. Graham knew what kind of book I'd write. That's why he wanted me. The family have over-reacted and should simply grow up."

Additional reporting by Malcolm Fitzwilliams

David Lodge on Graham Greene

"I am not a genius. I am a craftsman who writes books at the cost of long and painful labour." That's what Graham Greene once said. I think he is a craftsman. There's a kind of perfectionism about his work and I think he was a great master of English prose and a great essayist. He combined the features of adventure fiction within a complex spiritual and metaphysical frame, and this makes for a very unusual theme in English literature.

He reached into areas utterly different from what he had grown up with, identifying with the outcasts, the priests, the corrupt officials, teenage criminals. It's a terrific risk for a novelist to take, to create somebody from such an utterly different background to his own. He had such an extraordinary life and such an extraordinary character full of contradictions and paradox.

Nowadays celebrity seems to make you fair game for investigation, so it's a reflection of the taste of the culture, which is frankly very voyeuristic and particularly curious about people's sex lives.

David Lodge speaking at a festival in Berkhamsted yesterday to mark the centenary of Graham Greene's birth