After Betjeman, now Amis is revealed to be another dirty old man

In the world of books, this is fast becoming the Year of the Dirty Old Man. Weeks after a biography of poet John Betjeman revealed him to be a serial swooner over a succession of sturdy tennis girls, Kingsley Amis is now portrayed as a hopeless case of sex addiction.

The Life of Kingsley Amis, to be published this month, draws on new sources, including the famously uninhibited private correspondence between Amis and his closest friend, the poet Philip Larkin. The revealing letters detail the thoughts, feelings and numerous conquests of Amis during an adult life that produced a stream of celebrated fiction, including Lucky Jim, The Green Man and The Old Devils.

Amis, who died at 73 in 1995, is considered by many to be the finest comic novelist of his generation, but his biographer, Professor Zachary Leader, portrays him as an irresponsible, louche philanderer.

By 23, Professor Leader says, Amis had already enjoyed several flings during wartime service, with nurses, ATS (Auxiliary Territorial Service) girls, French and Belgian women and a South African lady with whom he had a liaison in a caravan in High Wycombe.

Once while stationed in Brussels with the Army, Amis got drunk and, in the same evening, slept first with a prostitute and then with a waitress, subsequently contracting scabies. He asked "the insoluble question" of whether he got the infection from the prostitute or the waitress, and if the former, whether he'd given it to the latter.

In his early twenties, Amis wrote at length to Larkin, giving him updates on his progress with the young woman who was to become his wife, Hilly Bardwell. In one, he reports she is "coming along nicely. She really likes jazz. Her breasts are concave on top. And she likes me".

In a letter the following year, Amis details his trauma after Hilly discovers she is pregnant with their first son, Philip, and they very nearly go through with a backstreet abortion. "I felt as if I had committed an outrage on a schoolgirl and then murdered her, leaving my identity card near the body," he tells his friend.

Marriage and two young sons - the second the novelist Martin - did not change the philandering nature of Amis. Professor Leader details long, drunken parties at the Amis home, in which every woman present was invited by the author to visit him in his greenhouse in the garden. "They knew what the invitation meant."

Eventually, his infidelity caused Hilly to follow suit, a situation, Professor Leader speculates, which led to the birth of a daughter, Sally, who was not Amis's. Sally died in 2000, knowing nothing of this.