How the polls got it so wrong

Not all the pollsters got it wrong. On the morning of the election, a set of strikingly accurate predictions was slapped on David Cameron’s desk. They had been compiled by Jim Messina and Lynton Crosby, the strategists who had been running a campaign derided as dull and repetitive. But, as their research showed, it was also effective. Messina is now back in his office in Washington DC.

‘We predicted 312 seats that morning to Lynton,’ he says. This was in line with the exit poll (316 Tory seats) that shocked Westminster. Yet, every day of the campaign, the polls had the Tories and Labour neck and neck. Did he ever doubt his methods? ‘No, not at all,’ he says. Crosby carried out daily tracker polls and Messina was conducting analytics. ‘Both of us had the same data, so we were very sure.’

Their working assumption was that all the polls used by the newspapers — YouGov, ComRes, Ipsos MORI — were talking rot.