The Conservative Party enjoys a 14-point lead over Labour, enough to give David Cameron an overall majority of 102, according to the latest poll by ComRes for The Independent.
It puts the Tories on 44 per cent, their highest rating since the company began polling for this newspaper in October 2006.
Labour is on 30 per cent and the Liberal Democrats on 16 per cent.
Although Tory support has risen four points since our last ComRes survey five weeks ago, their lead over Labour remains the same because Labour is also up four points. Other parties appear to have been squeezed. The Liberal Democrats have dropped four points, and the smaller parties have fallen back by the same amount.
Labour MPs were gloomy when they returned to Westminster yesterday for the first time since the party's crushing defeat in the Crewe and Nantwich by-election. Although many fear the party is heading for a general election defeat, there seems little appetite for an early attempt to force Gordon Brown to stand down. Some backbenchers said his position would be "reviewed" in the autumn but admitted they would need support from cabinet ministers to oust him. Cabinet members are reluctant to move against him.
While there will be some relief in Labour circles that the party's recent slide in the polls has been halted, there is little else in the new survey to cheer Mr Brown.
The Tories are ahead among every age group and social class. Labour, which has seen its traditional working-class supporters desert it following the abolition of the 10p rate of income tax, trails the Tories by 38 per cent to 35 per cent among the lowest DE social group and by 43 per cent to 30 per cent among C2 skilled manual workers.
Mr Cameron's party is ahead of Labour in every region of Britain except Scotland and enjoys a 10-point lead in Labour's former stronghold in the north of England.
The Tories' success in the local elections and Crewe by-election appears to have bolstered their standing among their natural supporters. Some 97 per cent of people who identify themselves as natural Tories say they will vote for the party, well ahead of the number of natural supporters intending to back Labour (73 per cent) and the Liberal Democrats (74 per cent).
Tory "identifiers" are also more likely to vote. Some 69 per cent of them say they are absolutely certain to vote, compared to 60 per cent of Labour and Liberal Democrat supporters.
The findings will be a setback for the Liberal Democrats, whose rating is lower than when Nick Clegg succeeded Sir Menzies Campbell as leader in December.
Today Derek Simpson, joint general secretary of the Unite union, will warn that Labour's loss of working class support could hand victory to Mr Cameron. "While we [in Labour] went blue from the lack of oxygen, the country has gone blue for the lack of social change," he will tell his union's conference in Brighton. Calling for New Labour to be consigned to the history books, he will say: "It is not the differences between Gordon Brown and Tony Blair that are the problem, it is the similarities." Frank Field, the former minister, will warn that Labour's core voters could defect to the BNP if the Government fails to address the "English question" arising from the creation of the Scottish Parliament.
ComRes telephoned 1,006 adults in Great Britain on 30 May to 1 June. Data were weighted by past vote recall. ComRes is a member of the British Polling Council and abides by its rules. Full tables are at www.comres.co.uk