David Cameron has been accused of "running scared" after signalling that he wants to see changes to the format of the televised debates with other party leaders introduced in the 2010 general election if he is to take part again in 2015.
Cameron told a Westminster lunch he was in favour of the debates in principle, but felt that in 2010 they sucked the life out of the rest of the campaign.
The prime minister said he had not yet decided whether to sign up for another round of TV clashes and indicated that if they did go ahead, he would favour a less formal format for the debates.
"I think TV debates are good. I enjoyed them last time - particularly the last one," he said.
"We have a fixed-term parliament now, so we can think about it in a slightly different way. I haven't made my mind up exactly what we should do but I am in favour of these debates.
"My reflection on last time was that they did take all the life out of the campaign.
"The press and all of us were interested in the run-up to the debate, the debate and the post-debate analysis, not the rest of the campaign, which I really enjoy.
"I like campaigning, I like being out there, the public meetings, the awkward moments, the difficulties - it is an incredibly exciting time, trying to explain what you are about and what you are trying to do.
"I found the TV debates took all the life out of it."
Michael Dugher, Labour's vice-chairman, said Cameron's comments showed he was "weak, out of touch and running scared of the public".
"At the next election, David Cameron should have to defend his decisions and his record - from a disastrous economic record to the fact that we now have fewer nurses in our NHS and fewer police officers fighting crime.
"The public will rightly want to see him and Ed Miliband questioned properly about what changes we need for the future of the country, including during the General Election campaign itself.
"Ed Miliband relishes the chance to debate with David Cameron. Cameron cannot be allowed to ditch the TV debates simply because he is too scared to defend his record."
Britain's first-ever televised general election leaders' debates, between Cameron, Gordon Brown and Nick Clegg, were staged on 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.
"We started with TV debates that were easy to agree, because they were quite controlled," said Cameron.
"I think that was right because we wanted everyone to sign up, but as a result they were quite dry - what really mattered was just delivering the soundbite down the camera, rather than a proper debate and more interaction.
"I think we could learn from last time. I have got an open mind and there is still two and a half years to go before we have to really think about it.