A combination of pictures shows different views of an exit poll projection predicting a swing to the Conservative Party in Britain's 2015 general election
London (AFP) - The Conservative party's unexpected triumph in Britain's general election delivers a hefty blow not only to the routed Labour party, but also to the pollsters who predicted a dead heat.
"The pollsters need to go off and interrogate themselves and poll each other to find who has been telling porkies to whom," concluded Conservative London mayor Boris Johnson.
"It's extraordinary that 11 polls on the eve of the election should get it so wrong."
For months, the main survey-takers had the two parties neck-and-neck, flatlining at around 35 percent each.
Only one day before the elections, YouGov, ICM and Survation called it a tie and three other polls published by TNS, Opinium and ComRes gave the Conservatives the narrowest of leads.
Panelbase gave the Tories a two-point lead while all the newspapers wrote that a hung parliament was a certainty.
But when the first exit polls emerged as stations closed on Thursday at 2200 GMT, the shock was total, giving the Conservatives 27 seats more than the most optimistic of pre-vote polls and 77 more than Labour.
Those on the receiving end at first refused to believe the survey, recalling the memory of 1992 when the exit polls erroneously predicted a Labour victory.
If anything, the exit polls underestimated the scale of the Tory gains and Labour and Lib Dem defeats.
- 'Not our greatest moment' -
Former Liberal Democrat leader and campaign chief Paddy Ashdown, who were only predicted to win 10 seats, said he would "publicly eat his hat" if the results were correct.
On latest projections, the Liberal Democrats were set to get eight.
"What seems to have gone wrong is that people have said one thing and they did something else in the ballot box," explained Peter Kellner, president of YouGov.
"We are not as far out as we were in 1992, not that that is a great commendation," he told the Daily Telegraph.
Following the 1992 debacle, the pollsters redeemed their reputations by correctly predicting the difficult 2010 result, which led to a Conservative/Lib Dem coalition.
But they are now back to square one after the latest slip-up.
"The election results raise serious issues for all pollsters," admitted Populus in an official statement issued Friday.
"We will look at our methods and have urged the British Polling Council to set up a review."
Tony Travers, professor of politics at the London School of Economics, said the failings may be due to "a late surge" or "a methodological issue or long-term shy answering".
The conservative electorate is traditionally shy to pronounce its preference beforehand, and pollsters have often tended to overestimate Labour.
The most apparent failing appears to be in translating the percentages of voting intentions into the right number of seats, a tricky task in Britain's system in which coming second in a seat counts for nothing.
"The distribution of the seats may not be our greatest moment but in other areas I think we have done quite a good job," said Michelle Harrison from TNS.
She told Sky News that they had predicted many of the night's broad trends, including the almost total success of Scottish nationalists, who devoured Labour north of the border, and the disastrous impact of five years of coalition on the Liberal Democrats.