Tony Blair begins his first visit to the region as Middle East envoy on Monday, hoping he can help turn around 60 years of peacemaking failures since Britain ended its mandate over Palestine.

'Mission Impossible' is what the sceptics have, inevitably, already called the newly retired prime minister's mandate.

He has been asked by the Quartet powers -- the United States, European Union, United Nations and Russia -- to present by September an initial plan for building ruling institutions needed to establish a viable Palestinian state alongside Israel.

That more limited mandate, which he will discuss with Israeli and Palestinian leaders on a visit of barely 48 hours, may be expanded later into a more direct peacemaking role between the parties, a senior Western diplomat said on Sunday.

This week, however, Blair 'is coming very much in listening mode', a spokesman for the former British leader said.

Blair faces serious obstacles to success in a role that has doomed all his predecessors.

The goal of a state appears more remote than ever, with the Palestinian territories divided between Hamas Islamists in the Gaza Strip and President Mahmoud Abbas's secular Fatah faction in the occupied West Bank.

Israel's government may be too weak to deliver concessions such as the withdrawal of Jewish settlements. Many Arabs resent Blair's role in invading Iraq, and the Quartet remains divided over whether he should have a broader negotiating mandate.

In his favour may be eagerness among leaders on both sides to raise their stock at home by showing progress toward peace.

A close relationship with US President George W Bush may give added clout to Blair, a relatively youthful 54-year-old successful in peacemaking in his Northern Irish backyard.

'I hope I can offer something in bringing about a solution to this issue that is of such fundamental importance to the world,' he said in Lisbon last week after meeting US Secretary of State Condoleezza Rice and the rest of the Quartet.

Abbas wants Blair to pressure Israel to ease its military grip on the West Bank and take steps to accelerate negotiations.

Hamas, which routed Abbas's forces in Gaza last month, says the former British leader is pro-Israel and 'doomed to fail'.

Former World Bank President James Wolfensohn, who resigned from the post as Quartet envoy in frustration more than a year ago, said he was concerned Blair lacked authority. But asked by Israel's Haaretz newspaper of his prospects, Wolfensohn said: 'Better than mine were. He is closer to George Bush. He was prime minister. I do not believe there's much time.

'But we're fortunate to have somebody with experience.'

In Lisbon, Blair promised to bring an 'intensity of focus' despite his narrow mandate, a senior Western diplomat said.

Instead of a broad peacemaking role, the Quartet asked him to raise funds for the Palestinians, help build their governing institutions and promote their economic development.

But the diplomat, speaking on condition of anonymity, said Blair was likely to seize a political mediation role despite US qualms: 'It was pretty clear that he was not going to be bound by the strict terms of his mandate,' the diplomat said.

'If he sees wider opportunities, he'll go for it.'

hat could put Blair on a collision course with Israel, which has so far resisted US pressure to make concessions and negotiate final-status issues.

Prime Minister Ehud Olmert said at the weekend Israel would have to withdraw from 'many areas' of the West Bank and suggested this could only be accomplished through negotiations.

Israeli officials generally favour a narrower mandate for Blair that would leave the United States in charge of any talks.  -Reuters