A senior legal official who secretly warned the government of Israel after the Six Day War of 1967 that it would be illegal to build Jewish settlements in the occupied Palestinian territories has said, for the first time, that he still believes that he was right.

The declaration by Theodor Meron, the Israeli Foreign Ministry's legal adviser at the time and today one of the world's leading international jurists, is a serious blow to Israel's persistent argument that the settlements do not violate international law, particularly as Israel prepares to commemorate the 40th anniversary of the war in June 1967.

The legal opinion, a copy of which has been obtained by The Independent, was marked "Top Secret" and "Extremely Urgent" and reached the unequivocal conclusion, in the words of its author's summary, "that civilian settlement in the administered territories contravenes the explicit provisions of the Fourth Geneva Convention."

Judge Meron, president of the International Criminal Tribunal for the former Yugoslavia until 2005, said that, after 40 years of Jewish settlement growth in the West Bank - one of the main problems to be solved in any peace deal: "I believe that I would have given the same opinion today."

Judge Meron, a holocaust survivor, also sheds new light on the aftermath of the 1967 war by disclosing that the Foreign Minister, Abba Eban, was "sympathetic" to his view that civilian settlement would directly conflict with the Hague and Geneva conventions governing the conduct of occupying powers.

Despite the legal opinion, which was forwarded to Levi Eshkol, the Prime Minister, but not made public at the time, the Labour cabinet progressively sanctioned settlements. This paved the way to growth which has resulted in at least 240,000 Jewish settlers in the West Bank today.

Judge Meron, 76, is now an appeal judge at the Tribunal. Speaking about his 1967 opinion for the first time, he also tells tomorrow's Independent Magazine: "It's obvious to me that the fact that settlements were established and the pace of the establishment of the settlements made peacemaking much more difficult."

Blaming restrictions on Palestinian movement for the devasatation of the Palestinian economy, the World Bank earlier this month acknowledged Israeli security concerns but added that many of the restrictions were aimed at "enhancing the free movement of settlers and the physical and economic expansion of the settlements at the expense of the Palestinian population." The settlements and their "jurisdictions" effectively control about 40 per cent of the area of the West Bank .

The argument that the settlements are illegal, stated in successive UN resolutions, and by the International Court of Justice advisory opinion condemning the separation barrier in 2004, is reinforced by such an authoritative source. It strengthens the political case in any "final status" negotiations on borders with the Palestinians for genuinely equitable land swaps of Israeli territory to a future Palestinian state if Israel is to retain settlement blocks.

Prime Minister Ariel Sharon secured a promise in 2004 from President George Bush that large Israeli "population centres" in the West Bank could remain in Israel in any such negotiations. In a subsequent letter to the Palestinians, the President promised that final borders had to be subject to agreement by negotiation.

Judge Meron's memorandum was obtained from the Israel State Archives. His subsequent defence of it amounts to a direct challenge to Israel 's continuing contention that the Geneva Convention's provisions on settling people in occupied territory did not apply to the West Bank because its annexation by Jordan between 1949 and 1967 had been unilateral.

The memorandum was written in September 1967 as the Eshkol government was already considering Jewish settlements in the West Bank and the Golan Heights, seized from Syria during the Six Day War. It says that the international community had already rejected the "argument that the West Bank is not 'normal occupied territory'."

It pointed out that the British ambassador to the United Nations, Lord Caradon, had already asserted that Israel 's position was that of an occupier. It added that a decree from the army command saying that military courts would "fulfil Geneva provisions" indicated that Israel thought so too.

Judge Meron also says in his interview that such an argument would not in any case have applied to the Golan Heights which had been undisputed as sovereign Syrian territory prior to the Six Day War.

While the Olmert government has so far rejected calls for peace negotiations by Syria 's President Bashir Assad, it has been weighing a welter of internal advice proposing that it explores talks seeking an end to Syrian support for Hizbollah and Hamas in return for restoring the Golan Heights to Syria .

The memorandum, details of which were published by the Israeli writer Gershom Gorenberg last year, also says settlements built on private land would explicitly contravene the 1907 Hague Convention.

The only implicit acknowledgement of the Meron memorandum - which Mr Gorenberg established also went to Moshe Dayan, the triumphant Defence Minister during the Six Day War - was that one of the first West Bank settlements, Kfar Etzion, was initially called a "military outpost" although it was already, in effect, a civilian settlement. The memorandum said there was no legal prohibition against military posts in occupied territory.

Ehud Olmert fought the Israeli election last year on a programme of unilateral withdrawal from parts of the West Bank - usually thought to mean dismantling settlements east of the separation barrier, which cuts deep into the West Bank in places. But this strategy was abandoned after the Lebanon war.

Mark Regev, the foreign ministry spokesman, said yesterday: "We do not accept that the West Bank is occupied in the classic sense." He added that it was not sovereign Jordanian territory before 1967 and it had not enjoyed legal status since the British mandate, which had the remit, underpinned by the League of Nations , of establishing a Jewish national home.

http://news.independent.co.uk/world/middle_east/article2584164.ece