His career over, Sharon is left to fight for life

Ariel Sharon, the Israeli Prime Minister, was today undergoing further surgery - fighting for his life as his closest allies began to realise that his political career was over.

He had been under heavy sedation and connected to a respirator after what was officially described as an "extensive" stroke, the second in three weeks, and a massive brain haemorrhage. The fresh surgery followed what doctors said was a "rise in cranial pressure".

Mr Sharon's illness, which aides privately accept spells the end of his five-year premiership and more than a half a century of operating at the centre of Israeli military and political life, leaves the biggest political vacuum in the country since the assassination of Yitzhak Rabin a decade ago.

Insisting on anonymity, one of more than 30 close aides allowed to maintain a vigil next to the operating theatre during Mr Sharon's two sessions on Wednesday night and yesterday morning admitted the Prime Minister would never return to office. "Now the main question is whether the doctors will be able to save his life," he added.

Professor Shlomo Mor-Yosef, director of Jerusalem's Hadassah Ein Karem hospital, told reporters: "The Prime Minister is suffering from low intracranial pressure, and is heavily sedated. He will be ventilated for at least the next 24 hours, and perhaps even for the next few days."

Professor Mor-Yosef said he had come to refute rumours "flooding the country" that the Prime Minister had already died and sought to pre-empt suggestions that 77-year-old Mr Sharon was in a worse condition than doctors admitted. "As Hadassah's director, I am obligated to bring every change in the Prime Minister's condition to light through statements," he said.

Doctors refused to confirm Mr Sharon had suffered irreversible brain damage. The aide said he would stay under sedation for three or four days to allow his brain to recover from eight hours of surgery and added: "Nobody is able at this point to give a damage assessment, but we know that there has been a great deal of damage. The extent will not be determined until he is woken, if he's able to be woken."

There was also no confirmation of widespread reports that one factor that triggered the brain haemorrhage Mr Sharon had on Wednesday night may have been the blood-thinning medication he had been taking since his first stroke three weeks ago. Yesterday he was to have had a relatively routine procedure to close the small hole in the heart thought to have contributed to the first stroke.

Professor Mor-Yosef said Mr Sharon had emerged from surgery with vital signs showing "functional and stable" levels, and a CT scan showing the bleeding in his brain had been halted. But he acknowledged his condition remained "grave". Amid saturation print and broadcast coverage of the Prime Minister's illness, Israel's largest mass-circulation daily Yedhiot Ahronot proclaimed in a banner headline, "The final battle" .

Israel's two chief rabbis, representing the Ashkenazy and Sephardic communities, joined in calling for the people to recite five psalms, and goodwill messages poured into the Hadassah from international leaders and Israeli politicians across a wide spectrum of opinion. At a cabinet meeting convened by Ehud Olmert, his deputy and now acting replacement, an empty chair was left for the absent Prime Minister.

But amid the widespread sympathy for Mr Sharon, Israel was also gripped by immediate speculation over the country's political future without the man who has overwhelmingly dominated its public life for the past five years.

Meir Shetreet, the Transport Minister and a prominent member of Kadima, the centre party formed by Mr Sharon to fight the 28 March general election, said the new party's founding members should convene in the next 48 hours to decide the leadership. Mr Shetreet suggested the party should rally behind Mr Olmert as its new leader. Mr Shetreet acknowledged Mr Sharon's personal influence had been "decisive" in helping to put the party at the top of opinion polls but said he believed that people would continue to support it if it adhered to Mr Sharon's legacy.

Diplomats and leading Israeli analysts suggested the party could prevent itself imploding-and indeed maintain much of its support if it took a quick and unacrimonious decision to appoint a new leader to take on Labour's Amir Peretz and Likud's Benjamin Netanyahu, the former prime minister.

Uri Dromi, of the Israel Democracy Institute and a former senior aide to Yitzhak Rabin and Ehud Barak when they were prime ministers, said Mr Olmert could well emerge as an effective potential prime minister in the three months up to the election, strengthening his pitch if endorsed by Kadima. "He is very capable and very shrewd and he can take decisions."

Mr Olmert, a former Likud hawk who, as mayor of Jerusalem, did much to foster controversial Jewish settlement in Arab East Jerusalem, is now the most "doveish" of Mr Sharon's immediate allies and has gone further in hinting at Iraeli withdrawals from the West Bank.

Mr Dromi said the electorate would be much less likely to take on trust the barely adumbrated Kadima programme, particularly on relations with the Palestinians, with a new leadership than it had been with Mr Sharon. But he said Mr Olmert would be capable of such a programme. "I think he can say, 'Guys, the dream of a greater Israel is dead' in a precise way Sharon wasn't willing to do. He can say, 'You all know you can't keep the Palestinian territories forever and remain a Jewish democratic state'."

Professor Yaron Ezrahi, a leading Hebrew University political scientist, said: "Under present circumstances, a coalition between the centre party and the left is most probable."

He said Mr Netanyahu would try to make a pitch to Kadima's centre ground but would be constrained by his support from the main settler organisation which backed him for the leadership, and by Likud's ultra-nationalist extremist Joseph Feiglin.

He rejected suggestions that Mr Netanyahu would be able to capitalise on his contention that security fared better under his premiership than under Mr Sharon's. He said Israelis would regard him as "unreliable" with problems such as internal Palestinian violence or the nuclear threat from Iran. "In the face of threats like this, the last person they want taking decisions is Benjamin Netanyahu," he said.

Recovery from serious strokes is unpredictable

Complete recovery from a stroke as serious as Ariel Sharon's is unlikely. The length of his operation - seven hours - itself carries risks and the damage is likely to be severe.

But the outcome is unpredictable and miraculous recoveries have been made. Giles Elrington, consultant neurologist at St Bartholomew's Hospital, London, said: "If I saw a person in his condition and with his history, I would say to the family, 'I don't think Dad is likely to go back to work after this'. But he is not a normal person; he is the leader of a country and he would be well supported."

Everything depended on whether the affected part of the brain was dead or only temporarily damaged, he said. "People will make the most incredible recoveries against the odds from stroke.

"Someone who appears badly affected in the early stages may come back, and someone who suffers slight damage may fail to progress.

"It is so variable. The wise clinician, even if he has seen the brain scans, will play his cards close to his chest."

Mr Sharon is being kept under deep sedation. The commonest stroke is an infarct or blockage in an artery in the brain caused by a blood clot, which accounts for 80 to 90 per cent.

The other kind are brain haemorrhages of the sort suffered by Mr Sharon, where there is a bleed into the brain. Sometimes brain haemorrhages follow infarcts.

Jeremy Laurance, Health Editor