Conservative politician who runs polling company attacks competitor's survey after it shows Ed Miliband winning leaders debate

A Conservative peer who runs a polling company has criticised a poll by one of his competitors after it showed Ed Miliband winning Thursday’s leaders debate.

Lord Cooper of Windrush, the director and founder of the polling company Populus, was appointed to the House of Lords by David Cameron and was previously the prime minister’s director of strategy.

After a survey by pollster Survation last night found that Ed Miliband had won the contest, Andrew Cooper tweeted: “Shock news just in: Mirror poll says Miliband won”.

He later added: “There is a reason that the British Polling Council requires its members to disclose who has commissioned polls!”

The comments were widely interpreted as implying that the Daily Mirror, a Labour-supporting newspaper which commissioned the survey, wanted a poll which showed Ed Miliband as the victor.

Keiran Pedley, the associate director of another pollster, Gfk, tweeted: “Come on! You know better than that” while Conservative commentator Tim Montgomerie described the outburst as “a bit cheap”.

Both Survation and Populus are members of the British polling council and abide by its rules – meaning their methodologies are kept public and open to scrutiny.

The peer told the Independent that he blamed the newspaper rather than pollster for what he said were problems with the methodology of the poll.

“The lack of objectivity I referred to was – plainly – the Mirror’s,” he said, arguing that the sample of the poll had a “pro-Labour skew compared with the consistent picture of voting intention polls overall”.

“In my view that skew makes it difficult to argue that any of the data means anything. It is actually impossible to do a post-debate poll that means anything because there is literally no way of knowing what a representative sample of the viewing audience would look like.”

The Conservative peer clarified: "I did not say – and am not saying - a competitor’s poll is biased. I am saying it isn’t weighted properly and therefore the data is skewed."

He added that he believes the Daily Mirror would welcome a poll showing a Miliband victory due to its Labour leanings.

But Damian Lyons Lowe, the founder on Survation, told the Independent that that the survey's methodology was open and that the pollster stood by it.

“Andrew Cooper has made critical comments about the polling methodology even before he had seen the data tables and the methodology,” he said.

“Survation stands by the methodology chosen and full information about it is available in public on our website for everyone to see – we like to be very transparent about the way that we work.”

The poll of last night’s contest found Ed Miliband ahead with a comfortable 35% of the audience believing that he won. SNP leader Nicola Sturgeon was just behind on 31%.

Ukip leader Nigel Farage was preferred by 27% of the audience with Green Party leader Natalie Bennett and Plaid Cymru leader Leanne Wood placing far behind on 5% and 2% respectively.