LONDON // It was one of the most horrifying incidents that occurred in the long, brutal and tragic Lebanese civil war.
Between 800 and 3,500 people were killed - mostly older men, women and children - by Israeli-backed, far-right Christian Phalangist militias between September 16 and 18, 1982.
The Israeli army had invaded Lebanon in June of that year in an attempt to remove the Palestinian Liberation Organisation and its leader, Yasser Arafat, and had succeeded in forcing their departure a week earlier.
But the Israeli military remained to find and expel any Palestinian fighters still in Beirut and had set up encampments outside the Palestinian refugee camps in Sabra and Shatila.
As the Phalangist militiamen - also looking to flush out Palestinians - rampaged through the narrow alleys of the camps at night, Israeli soldiers fired flares to light their way.
The bloodshed shocked the world and sparked a wave of criticism that would eventually force Israel's withdrawal.
But classified documents released last week under the British government's 30-year disclosure rule suggest the massacres of Palestinians at the Sabra and Shatila camps in 1982 did little to change the thinking of the international actors in the conflict.
Instead, power brokers in London and Washington distanced themselves from the conflict, reluctant to become embroiled in domestic debates over Israel's actions.
The initial revulsion at the killings was significant. Margaret Thatcher, the British prime minister, released an early statement calling the massacres an "act of sheer barbarism which must bring total condemnation on its perpetrators".
In private communications, Francis Pym, the British foreign secretary, described the killings as "appalling" and a "slaughter".
But Pym also seemed to absolve Israel of direct responsibility for massacres.
In an initial assessment dated September 20, Pym wrote that while the Israelis had been "guilty of incompetence, miscalculation, overeagerness to clear out the remaining PLO and unwise dependence on undisciplined militia", he would "exclude the idea that the Israeli were directly involved in the killings".
In the same assessment, Pym also predicted that whatever the truth, the Israeli government would try to "brazen it out" and reject any responsibility.
The killings in Sabra and Shatila had come after a nearly three-month Israeli siege of Beirut, which, by some estimates, killed as many as 40,000 civilians and levelled much of the city.
The PLO, and its leader Yasser Arafat, left Lebanon on August 30, 1982, for Tunis. But the fighting continued among the many Lebanese factions - whether Christian, Sunni, Shiite or secular - as well as Syrians, Israelis and the remaining Palestinians
Just two days before the massacre, Bashir Gemayel, the president of Lebanon and a Phalangist leader, was assassinated by Habib Shartouni, a Maronite Christian socialist who later said he had acted because "Bashir had sold the country to Israel".
Phalangist militants entered the camps "steeped in hatred for Palestinians", an Israeli commission of inquiry later conceded.
For weeks after the incident, the Israeli government refused to countenance an official inquiry or take disciplinary action against senior officers or the minister of defence, Ariel Sharon.
Their intransigence angered US president Ronald Reagan.
In a September 24 communiqué to Thatcher, Pym noted that American criticism of the Israeli prime minister, Menachem Begin, had reached "unprecedented levels" after the massacres and ascribed to Reagan "growing frustration" and "irritation" when dealing with Israeli leaders.
The US president had sent marines on August 21 as part of a multinational force of American, French, British and Italian soldiers meant to escort the PLO out of Lebanon.
After the massacres and the Gemayel assassination, Reagan's initial reaction was to reconstitute and redeploy the international force, which had left Lebanon after the PLO withdrawal.
But in the same communique, Pym said Reagan was wary of becoming "involved in the political debate in Israel".
Already, administration officials were resisting calls for an increase to a proposed US$2.4 billion (Dh8.8bn) aid package to which Israel's "friends in Congress" had already succeeded in adding $650 million in military grants and as cover for debt repayment for US loans, //PYM WROTE?//.
Britain, meanwhile, also baulked at a US request for greater input to the international force . In one handwritten note, Thatcher even told Pym: "We just can't. We are already overstretched."
Under US pressure, she relented to some degree and agreed to a "purely token" contribution.
When the White House in June 1983 asked Thatcher's secretary Robert Armstrong whether she would agree to expand that role or form a Commonwealth force, she again picked up her pen.
"We can't do either and we must be very firm and frank about it. We cannot overstretch ourselves any more. No need for a discussion," Thatcher wrote.
By then, the horrors of Sabra and Shatila had receded and the role of the international force would be reconsidered again only after the October 23, 1983, lorry bombing of the US marine base in Beirut that killed 241 American servicemen.
The force was withdrawn in February 1984 and Lebanon's civil war lasted until 1990.
The Israeli occupation arguably has not ended despite the withdrawal from South Lebanon in 2000 - it still controls the Shebaa Farms area which Syria considers a part of Lebanon, although the UN and Israel consider it a part of Syria. And Syrian forces, which entered the conflict in 1976 with a mandate from the Arab League, only withdrew in 2005.
The massacres at Sabra and Shatila had little effect on the political fortunes of those in positions of authority at the time.
While he was censured in early 1983 by an Israeli commission of inquiry - that otherwise absolved Israel of blame - and barred from the post of minister of defence, Ariel Sharon returned as prime minister in 2000.
Amine Gemayel, Bashir's elder brother, was president of Lebanon until 1988, when he left for a 12-year voluntary exile. He returned in 2000 and in 2008 was elected head of Lebanon's Phalangist political party.
As for the Palestinian-Israeli conflict - always a subtext of the massacres, the pretext for Israel's invasion of Lebanon and now the focus of renewed negotiations - little there has changed.
In a September 1983 exchange at the White House, Thatcher warned Reagan of the dangers of continued Israeli settlement building. The American president complained of Arab intransigence but also conceded that, according to the official British notes, "the whole process depended on Israel being willing to give up territory for security".