For a start, Olmert has chosen to stress more than once during the election campaign in the past three weeks that he enjoys an "excellent personal relationship" with Tony Blair. Secondly, it shows that he is determined to put his own stamp on the way the job is done.

And thirdly, it underlines a confidence that he will be able to form a government as prime minister after next Tuesday's general election.

Olmert is one of the most experienced and skilful politicians in Israel. But the fact that a man who three years ago came only 34th in his party's list of parliamentary candidates should now be on the brink of one of the world's highest-profile and most important jobs is partly due to a series of events that could never have been foreseen a mere five months ago. The formation of the breakaway Kadima Party was set in motion by the unexpected Labour leadership victory of Amir Peretz. The propulsion of Olmert into the job of acting prime minister happened because of the massive stroke suffered by Ariel Sharon in January. And finally, Hamas's victory in the Palestinian elections has created a new set of challenges for which Sharon was unable to plan.

Born in 1945, Ehud Olmert spent his infancy at the heart of the militant underground fight for a Jewish state and independence from British rule. His parents were both members of Menachem Begin's right-wing Irgun. He lived for the first three years of his life at a Turkish-built fortress near Binyamina, in the north of what was still Palestine. After independence, the family moved to Binyamina itself, where his father became active in Begin's Herut. A generation later it would become the key component of Likud, the dominant right party that Olmert and Ariel Sharon left five months ago to form Kadima, now favourite to win Tuesday's election.

Married to the left At the age of 28 Olmert became the youngest member of the Knesset and came to immediate notice, mounting a fierce onslaught against corruption in public life. In 1975, he began a highprofile campaign to prove that Rehavam Ze'evi, a former army general and adviser to Yitzhak Rabin, had criminal connections, which ended when Ze'evi agreed to withdraw a libel suit if Olmert stopped harassing him.

Gradually he became less of a Likud superhawk. He voted against Begin's 1978 peace treaty with Egypt . . . something which he admitted he had been wrong about. But by 1990 he had become one of the 'Likud princes' who urged Shamir to back the American call for peace negotiations with Israel's Arab neighbours and the Palestinians which led in 1991 to the Madrid conference.

After Benjamin Netanyahu won the Likud leadership in 1992, Olmert set about building a second political base by securing the mayoralty of Jerusalem. He built settlements in East Jerusalem, and persuaded Netanyahu to build a tunnel from the Western Wall to the Muslim Quarter of the Old City, triggering riots that left 70 Palestinians and 15 Israeli soldiers dead. His supporters say he secured $100m for Arab areas in the city and the problems of the mayoralty were largely caused by the intifada; his critics say that he ran up a $110m deficit, partly through funding ultra-Orthodox projects to boost his standing among religious parties.

What is not in doubt, however, is that he was one of the first Likud politicians to abandon the idea of a 'Greater Israel' from Jordan to the Mediterranean; having been plucked back into national politics, he became Sharon's staunchest ally in the disengagement from Gaza last August, and he now intends more withdrawals of settlers from the West Bank.

Indeed, he is fighting the next election on the bold promise of drawing Israel's permanent borders within the next four years, by negotiation if possible, unilaterally if necessary, which most Israeli voters appear to think it will be.

If he were to go further than he has so far indicated he is likely to find a close ally at home. His reputation for greyness belies his liking for large Havana cigars, designer clothes and relatively upper-end lifestyle. He recently sold his handsome house in the Katomon district of Jerusalem for $2.7m to find a smaller one and he takes his fitness seriously, jogging up to 10km a day. He is a fanatical supporter of Betar Jerusalem football club and Hapoel Jerusalem basketball team.

But least grey of all is his long and happy marriage to Aliza Richter, a daughter of Holocaust survivors, who gave up her social work to become a successful author, sculptor and painter. For Aliza Olmert has pronounced left views. Asked recently about his wife's future role, Olmert said she herself had indicated she would be "neither Hillary Clinton nor Sonia Peres, " the latter a byword for wifely invisibility.

Two crucial questions about Olmert remain unanswered ahead of the election. Firstly, whether as a prime minister without Ariel Sharon's charismatic and formidable military past he has the same power to see off settler opposition to even the partial withdrawals he plans. And secondly, whether the US administration, his friends in Europe like Tony Blair, or even his wife are prepared to try to persuade him to do more than use the election of Hamas as a justification for limited and purely unilateral steps and even seek the kind of agreement which the Palestinian president Mahmoud Abbas insisted last week, however improbably, could be struck within a year.