Ariel SharonAriel Sharon’s erstwhile friends among the settlers are calling it death by “friendly fire”. The Israeli prime minister and champion of Jewish colonisation of the Palestinian lands occupied in the 1967 Arab-Israeli war has stunned his supporters and wrong-footed his adversaries by announcing his plan to evacuate the settlements in the Gaza Strip. Seen in its proper perspective, however, it is less a startling move than a very cunning one.

Mr Sharon let his withdrawal plan dribble out in an interview with the Ha’aretz newspaper and in remarks to his party, the right-wing nationalist Likud. He spoke of evacuating 17 of the 20 settlements in Gaza. “I am working on the assumption that in the future there will be no Jews in Gaza,” he said.

This is a bombshell for the settler movement Mr Sharon did so much to create, as well as for irredentists who regard all Eretz Israel – the Biblical Land of Israel – as given to the Jews by God. Others claim he is giving in to terrorism, in this case rewarding Hamas, the Palestinian Islamist group, rather than Hizbollah, the Shia movement that emerged as the political beneficiary when Israel withdrew from Lebanon in 2000 after a long war of attrition against its occupation. Some recall it was Mr Sharon himself, as defence minister, who withdrew settlers from an outpost in Egypt’s Sinai peninsula in 1982.

Yet it was also in that year that Mr Sharon conceived his strategy for securing for Israel the bulk of the occupied West Bank. The map he drew up in 1982 – known as Military Order Number 50 – is practically identical to the division of the West Bank envisaged under the so-called security wall now carving up Palestinian territory. This structure is enclosing the Palestinians inside an area amounting to 44 per cent of the West Bank, or about 9 per cent of historic Palestine. It is, and is widely seen as, a de facto annexation, as well as a death-blow to any hopes of a negotiated and just peace. What better, then, than this gambit in Gaza?

The Gaza settlements are not just morally indefensible – 7,576 colonists live in garrisoned enclaves among 1.3m Palestinians but use 40 per cent of a land scarcely bigger than Martha’s Vineyard – but physically undefendable. Israel, moreover, has never made religious claims on Gaza, and regards it as strategically insignificant. At the same time, appearing to give up so much will make it easier to take elsewhere – from the West Bank.

For the heart of the Sharon strategy is the wall enclosing the most populous areas of the West Bank. Ostensibly to keep out suicide bombers, it is placed deep inside Palestinian land and designed to keep all the main settlements under permanent Israeli control. A withdrawal from Gaza would be good news – for the Palestinians who live there as well as the Israeli soldiers who try to police it. But the wall will remain a barrier to peace and guarantee that this conflict will continue into yet another generation.