The BBC's TC1 Television Studio, site of the 2010 election debate. Image: Nick Garrod / Flickr
The broadcasters - ITV, the BBC, Channel 4 and Sky News - started with three proposed debates: a 2/3/4 format, in which there would have been Cameron v Miliband, Cameron v Miliband v Clegg, and Cameron v Miliband v Clegg v Farage, all to take place between 2 and 30 April.
Everyone except Cameron said yes to that (the Greens, Plaid Cymru, the SNP and the Democratic Unionists seemed resigned to their non-appearance).
