Pollster blames 'reluctant Tories'
Voters reluctantly opting for the Conservatives on polling day may have skewed pre-election opinion surveys, according to a leading pollster.
Peter Kellner, president of YouGov, suggested that it was not "shy Tories" that altered the polls but rather voters who felt they had no other option once "in the privacy of the polling booth".
The British Polling Council (BPC) has launched an inquiry into the pollsters' accuracy after almost every election poll during the campaign underestimated the Tories' lead over Labour.
Mr Kellner said the inquiry would need to probe the possibility people were unwilling to disclose their true intentions but said he put it down to "human psychology" instead.
He said: "This is likely to be one line of investigation of an inquiry by the British Polling Council. Obviously I can't be certain what it will find: if I were, I hope I would have acted to avoid the error in the first place. Here, though, is my initial, tentative suggestion.
"It comes down to human psychology. Voting is a different exercise from answering a poll. It is a choice with consequences, not just an expression of a view. This year, as in 1992, the Tories have a weak image. They are widely thought to be out of touch and for the rich.
"But at the margin, there may be some people who both have a poor view of the party but nevertheless think it will run the economy better than Labour. They are 'shy Tories' not because they are unwilling to admit their choice of party to a stranger but because they really would like to support someone else but, faced with a ballot paper in the privacy of the polling booth, simply can't."
The inquiry comes after political observers were shocked to see an exit poll showing the Tories comfortably ahead of Labour as the largest party, which was then followed by David Cameron's party winning an overall majority.
In the run-up to polling day, almost every major national poll had predicted the race was neck and neck and too close to call.
In the end, the Conservatives won an absolute majority, with 331 seats and Labour on 232, a vote share of around 37% for Mr Cameron's party and 30% for the Opposition.
The BPC, which counts all major UK pollsters among its members, said in a statement: "The final opinion polls before the election were clearly not as accurate as we would like, and the fact that all the pollsters underestimated the Conservative lead over Labour suggests that the methods that were used should be subject to careful, independent investigation.
"The British Polling Council, supported by the Market Research Society, is therefore setting up an independent inquiry to look into the possible causes of this apparent bias, and to make recommendations for future polling.
"The membership of the inquiry will be announced in due course."