Labour's vote has also remained surprisingly resilient across the region, while the Liberal Democrats have suffered a serious collapse in support.
The Yorkshire Post can reveal the first comprehensive region-wide snapshot of voting intentions since 2005, which quashes the notion suggested by national polls that the Tories would make significant gains in Yorkshire if an election were called today.
The YouGov survey shows Conservatives flatlining on 29 per cent – no change from the General Election 20 months ago – and some good news for Labour, whose 42 per cent shows only a two point drop over the same period.
Both results contrast dramatically with a national "poll-of-polls" performance of around 36 per cent for the Tories and 34 per cent for Labour.
But Liberal Democrats will be dismayed that almost a year of Sir Menzies Campbell's leadership appears to have gone down badly in Yorkshire, coinciding with a devastating 15 per cent showing – down six points since May 2005 – compared to 18 per cent nationally.
Most surprising of all is the leap in support across Yorkshire for smaller parties from seven to 15 per cent, evidence that a growing number of people are turning to the likes of the UK Independence Party, Greens and British National Party.
The poll comes as all Yorkshire and the Humber's 22 local councils prepare to go to the polls on May 3.
Yorkshire Tories last night called it a "wake-up call" for their leader but Cameron lieutenants insisted the modernising strategy was resonating in the region.
Senior Labour Party figures in Yorkshire welcomed the results, which showed just 21 per cent of local voters aged 35 to 54 would vote Tory and that more than half of them would stick with the Government.
Former Home Secretary and Sheffield Brightside MP David Blunkett said: "It is very bad news indeed for the Conservatives, who have to do well on a regional level to stand a chance of being a serious alternative Government."
Sports Minister Richard Caborn, Sheffield Central MP, said the poll "shows there's still a huge amount of confidence in Labour".
Shadow Constitutional Affairs Secretary Oliver Heald, who was last year appointed the "Shadow Minister" responsible for co-ordinating campaigning in South Yorkshire, conceded that it painted a far bleaker picture for the party's potential performance in Yorkshire than recent national polls.
But he added: "People in Yorkshire are finally keen to hear what the Conservatives stand for and although our vote hasn't gone up, there's clearly a mood for change."
But there was a starker assessment from Shipley's Tory MP Philip Davies, who said: "It's a wake-up call that
proves the messages that might work in the Home Counties don't necessarily work up here and reaffirms my view that we need to be talking more about everyday concerns like crime and immigration, as well as the environment"
But Mr Cameron's press secretary denied that the party's strategy was wrong.
"David Cameron has made progress in the North and our research shows that the issues he's addressing are important everywhere ... We recognise that there is much more to do and that it's going to take a long time to win back trust, but we have made a good start."
Lord Wallace of Saltaire, president of the Yorkshire Liberal Democrats, put their performance down to "a dip" between polls, insisting they would make gains at the next General Election.
The YouGov poll was commissioned by Speakout, an anti-EU campaign founded and bankrolled by Yorkshire tycoon Paul Sykes. A spokesman said the results were proof that the attitude of the main parties towards Europe and immigration were pushing voters into the hands of fringe parties.
n YouGov interviewed 1,225 adults in Yorkshire and the Humber between January 8 and 12, 2007.

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