William Golding, the author of Lord of the Flies, the allegorical novel about childhood, admitted that he had once tried to rape a girl.

He confessed to the incident in an unpublished memoir which he wrote for his wife in an effort to explain how his own “monstrous” character had developed.

The attack is among the revelations about the Nobel prize-winning novelist in a new biography. It also turns out that when he was a school-teacher, Golding would pitch the boys in his care against each other in a real-life forerunner of his famous work.

John Carey, the literary critic and an emeritus professor of English literature at Oxford, has had access to the previously unseen archive of Golding, who died in his native Cornwall in 1993, aged 81. It comprises three unpublished novels, two autobiographical works and a journal of 2m words written over 20 years.

Golding comes across as a man of deep introspection who drank heavily to sustain himself. The biography also throws new light on how Lord of the Flies, his first and most famous novel, was published after many publishers rejected it.

It reveals how its editor altered it to exclude much material on the nuclear bomb and changed the character of Simon, one of the British schoolboys marooned on an island after a plane crash, from being too explicitly Christlike.

However, it is Golding’s attitude to women in his unpublished Men, Women & Now, which will cause most surprise in literary circles.

He had met the girl when both were taking music lessons in Marlborough, Wiltshire, when he was about 16 and she was 13, but he tried to rape her two years later when he was home during his first year at Oxford.

Golding writes that they went for a walk to the common and he “felt sure she wanted heavy sex, as this was visibly written on her pert, ripe and desirable mouth”.

Soon they were “wrestling like enemies” as he “tried unhandily to rape her”. But she resisted and Golding, all those years later, wrote that “he had made such a bad hand at rape” before shaking her and shouting “I’m not going to hurt you”.

Click here to read the full report from the London Times.