Televised leaders' debates were, for the UK, a major innovation in the 2010 General Election campaign. Though common in many other democracies, they have not previously featured in Britain. Inevitably, their likely influence on the election result was much debated both before and after the event. A substantial mid-campaign surge in support for the Liberal Democrats after the party's leader was widely seen as having won the first debate seemed to vindicate a claim of substantial effects, though over the remainder of the campaign Liberal Democrat support subsided and the other parties recovered, returning to nearly the same levels all had been at when the campaign opened. So were the effects of the debates very short term, or did their influence last until polling day? The paper employs panel data to assess the impact of voters' perceptions of how the party leaders performed in debate on their evaluations of the leaders, their parties, government performance and vote choice.