With just over a year to go until the general election, the issue of the leaders' TV debates remains unresolved. Both Labour and the Liberal Democrats are ready to sign up to a repeat of the "333" format (three debates between three leaders over three weeks) but the Tories are proving to be a stumbling block.

David Cameron, who has complained that the last set of debates "sucked the life" out of the 2010 campaign, has postponed all negotiations on the issue until after the party conference season. The Tories, many of whom wrongly blame the debates for their failure to win a majority at the last election, have long briefed that they would like the debates to be limited to one head-to-head contest between Miliband and Cameron (possibly before the campaign proper begins) or not to take place at all.

Now, Miliband has called Cameron's bluff. In an article for the new issue of the Radio Times, he writes:

It would be extraordinary if any political party tried to argue that cancelling TV debates would serve the interests of democracy. And David Cameron has been very careful, at least in his public utterances, not to do so. But no one should doubt that he is the single biggest obstacle to getting TV debates on at the next election.

He adds:

Mr Cameron wonders aloud if there were not too many debates last time. Whether they were held at the right time, or dominated the campaign too much. There have been reports that he wants to limit the number of debates to one – or none. It is a pity that the Conservatives will not even sit down to begin negotiations until later this year – when it will be harder to secure an agreement – and have stalled at every opportunity they have been given to do so. I can only assume that Mr Cameron wants his party’s deep pockets to be used for maximum advantage and that perceived political self-interest lies behind his party’s reluctance to get these debates on. But no one should want the outcome of the next election distorted by the number of direct mailshots and billboard posters a party can buy. And, while TV debates will not level the playing field on their own, they can help enable people to make better-informed choices when they cast their votes.

While conventional wisdom has it that Cameron would come out top in the debates (owing to his superior personal ratings), Labour strategists regard them as a significant opportunity for Miliband. They view the debates as a chance to bypass a largely hostile press and speak directly to voters and to provoke the PM into one of his unattractive "Flashman" rages. As Labour figures rightly note, as often as not, Miliband gets the better of Cameron at PMQs. With the Tories certain to outspend Labour, the debates are also a chance to reach millions of voters for free.

To this end, Labour has appointed party vice chair Michael Dugher and Miliband's director of strategy Greg Beales to lead negotiations with the broadcasters.

In a euphemistic reference to Nigel Farage, Miliband writes that the TV companies will "ultimately determine who is invited", but adds: "because I am not going to give the Conservatives the excuse to walk off the pitch by claiming we have moved the goalposts, the starting point for negotiations should be the agreement Mr Cameron signed up to four years ago: three debates between the three main party leaders over three weeks of the campaign. With the election just a year away, it is time Mr Cameron stopped dragging his feet and showed he is willing to debate the future of our country by allowing the negotiations to begin."

The biggest challenge now for Labour, as one senior source puts it, "is to avoid him [Cameron] getting out of it."