The Labour leader said the previous format of three debates between the three main party leaders should be a "starting point" but that he was open to moves such as a less formal setting and greater voter participation in any repeat of the 2010 confrontations. He used a Radio Times article to call for immediate negotiations, accusing his main rival of being the "single biggest obstacle" to them going ahead and suggesting the Tories were keen to deny his cash-strapped party vital publicity. Britain's first such debates, between Mr Cameron, Gordon Brown and Nick Clegg, were staged on the BBC, ITV and Sky News in 2010 after prolonged negotiations between the parties and the TV companies, which resulted in very strict rules on the style of questioning and the division of time for leaders' answers.
Mr Cameron has since complained they "took all the life out" of the campaign amid constant speculation over whether the practice would be revived, and if so in what form.
There is speculation that he could seek to exclude Mr Clegg, now Deputy Prime Minister in the Tory-led coalition.