Facing a charismatic new opponent, doubters in his party and a clock he set ticking on his own premiership, politicians and analysts say Tony Blair's departure date will dominate British politics next year.
At his year-end news conference on Wednesday, the prime minister would not discuss when he will stand down and pledged defiantly to press on with policies many in his party oppose.
"I've never felt more confident about the fact we are doing the right things for the long-term future of the country," he said. "I'm battling on all fronts but I'm enjoying battling." Blair has declared he will not fight a fourth election, expected in 2009, but intends to serve a full third term.
His allies insist he will remain until 2008 at least. Others in the ruling Labour party say he may be gone within a year. One thing is certain - new Conservative leader David Cameron has spiced up British politics and revived his party which has languished in opposition for over eight years.
An ICM opinion poll this week showed two-thirds of British voters think Blair's government has run out of steam, putting the Conservatives a point ahead of Labour on 37 percent - only the second time since 1993 they have led in an ICM survey.
European Trade Commissioner Peter Mandelson, a close Blair ally, said Labour faced a challenge from a leader far more appealing than his predecessors. "We are living in interesting political times," he told BBC Radio.
Cameron, at 39, is 15 years younger than Blair's likely successor, finance minister Gordon Brown. He has won plaudits for a natural, media-friendly style.
"Cameron changes the Conservative brand," said Philip Cowley, political analyst at Nottingham University. "Until now, nobody was prepared to listen them. Now they will and will take them seriously."
If Cameron stays ahead in the polls for several months, Blair loses key votes in parliament and Labour fares badly in next May's local council elections nation-wide, the prime minister's position could become increasingly shaky.
Cowley said mid-term election blues used to be expected of every government. Since 1997 Labour has never suffered them but will do so this time.
"That's not going to force Blair out but the majority of Labour MPs have never been behind like this before. There could be some panic," he told Reuters. The past year has produced signs of Blair's weakening authority since he put a time limit on his premiership.
His campaign for a third election win leant heavily on Brown's economic record as the legacy of Iraq continued to weigh on the prime minister.
Blair suffered his first major parliamentary defeat over terrorism laws and ministers have broken ranks to squabble over key policies like education reforms and banning smoking.
After May's election, it takes fewer than 40 Labour MPs siding with opposition parties to defeat Blair in parliament and having succeeded once, a disaffected rump plans to do so again.
Labour parliamentarians (MPs) say a series of legislative defeats would hasten Blair's demise. "Unless he learns to compromise he is in trouble," one said.
Yet if Blair waters down his plans, it would beg the question: why hang on when he cannot push through plans that anger Labour left-wingers, something he used to relish doing.
On education in particular, Blair has staked his authority on a bill that will be voted on in the first half of 2006.
Many Labour MPs believe his plans risk giving richer families more choice in schooling, leaving the poorer at the bottom of the heap. Normally loyal Deputy Prime Minister John Prescott publicly said so this week. Meanwhile, Brown's supporters say he is unable to take Cameron on effectively while Blair remains. They say he needs a decent stint at the helm to do so before the likely 2009 election.