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He confessed to the incident in an unpublished memoir which he wrote for his wife in an effort to explain how his own “monstrous” character had developed.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, on a 15-year-old named Dora, 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 It comprises three unpublished novels, two autobiographical works and a journal of 2m words written over 20 years.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However, it is Golding’s attitude to women in his unpublished Men, Women & Now, which will cause most surprise in literary circles.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 Dora 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”. Dora ran off.

After a gap of two years, they met again and consummated their relationship. Golding records her unromantic question, when she asked: “Should I have all that rammed up my guts?”

Golding tells how Dora persuaded his father, also a school-teacher, to spy on the two of them having sex in the open air. She suggested he take his binoculars with him on two specific days to a playing field where they would be. However, she knew that his other son Joseph, William’s older brother, would also be there with his girlfriend having sex.

“It was Dora’s revenge,” writes Carey, The Sunday Times’s chief reviewer. “She wanted to show him that his two sons were not exemplary.”

Carey is convinced that Golding was ashamed about his relationship with Dora, even though in Men, Women & Now he wrote that she was “depraved by nature” and he imagines her at 13 “beginning to burn” and says that at 14 she was “already sexy as an ape”.

Carey says that Golding “was aware of and repelled by the cruelty in himself and was given to saying that, had he been born in Hitler’s Germany, he would have been a Nazi. Dora seems to have played her part in this self-knowledge”.

A later girlfriend, Mollie, was also treated badly by Golding. She was another local from Marlborough whom he later let down by breaking off their engagement. He had found her frigid. Mollie is fictionalised by Golding in his 1959 novel Free Fall where the narrator falls for Beatrice, a local girl who was equally glacial.

This theme of cruelty and the issue of good and evil are central to Lord of the Flies and the boys stranded on the island. Golding’s argument in his novel is that, left to their own devices under strain, people will adopt extreme positions of human nature.

His own job as a school-teacher after Oxford had also given him an insight into the behaviour of boys. Golding on occasion would “stir up antagonism” between them to observe their reactions.

Once he took a group on a field trip near Salisbury and got them to form two gangs – one to attack a neolithic enclosure and the other to defend it.

He also admitted in his unpublished memoir that he used “a certain measure of experimental science” in his teaching to see what happened when boys were given more liberty. “I gave them more and my eyes came out like organ stops as I watched what was happening.”

His time as a teacher, interrupted by six years of wartime service in the Royal Navy, during which he was involved in the D-Day landings on the beaches of Normandy, helped to forge Lord of the Flies, which has sold 20m copies in Britain alone.

Golding’s drinking increased over the years. “Things like his war experience, the nervous breakdown of his own son David, who had been born with a club foot, and his inability to write as the years went on contributed to this drink problem,” said Carey last week.

The self-blame stayed through Golding’s life. “He actually thought he was a monster. Maybe because of how he had treated David as a child, or Mollie, whose life he had ruined when he left her, or the people he killed in the war.”

Carey’s postscript in the biography sums it up: “He saw the seeds of all evil in his own heart and found monstrous things, or things he accounted monstrous in his imagination.”

An extract of John Carey’s biography will be published in next week’s Culture

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