ComRes will use automated telephone polling to survey a minimum of 1,000 people in the minutes after the debates between the three main party leaders finish.

Respondents will be asked who they thought ‘won’ the debate, which party they plan to vote for, and two questions on specific topics covered in each debate.

Survey takers will be recruited from a panel of 15,000 people who have agreed to watch the broadcasts and be contacted afterwards.

The automated telephone polls are voiced by ITV newsreader James Mates, who will present the findings on that night’s ITV News at Ten.

Deborah Turness, editor of ITV News, said: “Rather than subjective discussion on which leader scored most points, through ComRes we will deliver the first scientific quantitative assessment of what the electorate really think. We believe that historic events such as the debates deserve unique analysis to show their impact.”

Labour leader Gordon Brown, his Conservative counterpart David Cameron and Liberal Democrat leader Nick Clegg have agreed to take part in three 90-minute debates on 15th, 22nd and 29 April.

During the debates, ComRes will be conducting ‘worm polls’ using a panel of 20 undecided voters in two key marginal constituencies in Bolton. As the leaders are talking, the panel will be watching and recording their satisfaction with what is being said using a handset. Scores are collated automatically and recorded in a time series of data forming a graph that will feature in further analysis of each debate on ITV News.