"It was decided and carried out: they washed her, cut her hair, raped her and killed her," he wrote.

After that the case became one of the state's earliest secrets, and no more than hearsay passed between soldiers.

Now the Israeli newspaper Ha'aretz has used previously classified army documents to reveal the full story of what Mr Ben-Gurion called a "horrific atrocity".

In August 1949, an army unit stationed at Nirim in the Negev shot an Arab man and captured a Bedouin girl with him. Her name and age remain unknown, but she was probably in her mid-teens.

In the following hours she was taken from the hut and forced to shower naked in full view of the soldiers. Three of the men then raped her.

After the Sabbath meal the platoon commander, identified by Ha'aretz as a man called Moshe who had served in the British army during the second world war, proposed a vote on what should be done with her.

One option was to put her to work in the outpost's kitchen.

Most of the 20 or so soldiers present voted for the alternative by chanting: "We want to fuck". The commander organised a rota for groups of his men to gang rape the girl over the next three days. Moshe and one of his sergeants went first, leaving the girl unconscious. Next morning, she complicated matters by protesting about her treatment. Moshe told one of his sergeants to kill her.

She was forced into a patrol vehicle with several soldiers, two carrying shovels, and they drove off into the dunes. When the girl realised what was about to happen she tried to run, but only made it a few paces before she was shot by a Sergeant Michael.

Her body was buried in a grave less than a foot deep.

A few days later the battalion commander, Yehuda Drexler, asked Moshe if he had carried out an order to return the girl to her village.

"They killed her," replied Moshe. "It was a shame to waste the petrol." He was ordered to write a report. Ha'aretz has obtained a copy.

It said: "In my patrol on 12.8.49 I encountered Arabs in the territory under my command, one of them armed. I killed the armed Arab on the spot and took his weapon. I took the Arab female captive. On the first night the soldiers abused her and the next day I saw fit to remove her from the world."

He and most of the soldiers at the outpost were tried in secret. Some said they were carrying out their commander's orders. The military judges rejected that line of defence. Moshe denied rape. "Morally speaking, it was impossible to sleep with such a dirty girl," he told the court.

He was acquitted of rape but convicted of murder and sentenced to 15 years in prison. The judges likened his stated willingness "to murder even women and children in cold blood" to "Hitler's methods in France".

Nineteen other soldiers received light sentences of between one and three years, mostly for "negligence in preventing a crime".

The appeal court reduced their sentences, saying: "At the time there was a general feeling of contempt for the life of Arabs ... and sometimes wanton events occurred in this sphere. All this helped create an atmosphere of 'anything goes'.

"We are convinced that this atmosphere existed at the Nirim outpost, too."

But the government and army understood the shame that would fall on the armed forces if the girl's fate became known to wider Israeli society, so the murder and trial were classified as secret.

The case was briefly resurrected at the trial in 1956 of Israeli soldiers and police officers who murdered 43 Arab civilians in Kafr Qassem, to help establish the precedent that there is no defence in obeying illegal orders.

Then it disappeared from view again.

Several years later members of a kibbutz near the Nirim base noticed that the wind had uncovered a small hand.