David Cameron has led his party to its strongest sustained position in 14 years according to a Guardian/ICM poll published today, which shows the Conservatives have extended their lead over Labour to eight points at the end of the new Tory leader's first year in office.
The poll puts the Conservatives on 40%, three points up on last month's Guardian/ICM result. Labour remain on 32% while the Liberal Democrats fall four points to 18%, their lowest rating in a Guardian poll since the summer.
The result underlines the big shift in public opinion that has taken place since Mr Cameron took over in December last year. Since then the Conservatives have averaged 37% in the Guardian/ICM series, four points ahead of Labour, which has averaged 33%. That is Labour's lowest annual average since 1992, the year that the Conservatives last won a general election.
The poll was carried out last weekend, after Tony Blair was questioned by police at Downing Street, and the party can draw comfort from the fact that its rating has remained unchanged.
Labour's resilient performance confirms a trend suggesting support for the party has hit a bedrock of just over 30% and will not drop below that.
Meanwhile Conservative support seems to have reached a maximum of 40%, almost certainly not enough to give Mr Cameron a majority at a general election. Although the result would leave him as leader of the largest party, Conservatives have yet to break through to an election-winning position.
The party will draw comfort, however, from the drop in Liberal Democrat support. Until now support for Sir Menzies Campbell's party has held firm despite Mr Cameron's attempts to appeal to the centre ground.
Underlying the shift in party support is the growing public belief that the Conservatives may be on course to win next time.
Only 12% of voters now think that the Conservatives will never win again, compared to 37% who think the party will win the next general election. When ICM last asked the question in July 2002, only 19% of voters thought the Tories would win next time.
Crucially, Conservative voters are now enthusiastic about their party's chances, with 67% saying they believe that Mr Cameron is on course for victory. That may encourage them to turn out and vote. By contrast, 29% of Labour supporters think that their party will lose to the Conservatives.
The poll also shows that the Green party, and not rightwing groups such as the UK Independence party, poses the biggest threat to the main three parties.
Despite recent publicity about Conservative defections to Ukip, and fears inside the party that Mr Cameron's remodelling of Conservative policy could alienate traditional support on the right, only 14% of Tory supporters say they might back Ukip instead.
Asked to name one or more other parties that they might support, Conservatives are much more likely to choose the Liberal Democrats or the Greens: 32% of Tories say they might vote Lib Dem and 19% say Green.
The result appears to strengthen Mr Cameron's hand in arguing the Conservatives must embrace a radical environmental and social justice agenda.
Labour supporters are also more likely to switch to the Lib Dems (30%) or Greens (16%) than Ukip (9%).
Nationally, Green support stands at 3% this month, against Ukip on 1%.
Around a third of Tory and Labour supporters say they would not consider changing their vote. Of those Labour voters who do say they might switch, 18% say they would consider voting Conservative and 30% Lib Dem.
· ICM interviewed a random sample of 1,006 adults aged 18+ by telephone between December 15-17. Interviews were conducted across the country and the results have been weighted to the profile of all adults. ICM is a member of the British Polling Council and abides by its rules.