David Cameron agrees to Sky News's terms for a general election leaders' debate

Televised election debates between potential Presidents and Prime Ministers are now commonplace across the world - but not yet in Britain.

We've seen similar encounters between candidates for the London mayoralty and First MInister of Scotland debating against each other, and in previous general elections the potential Chancellors have gone up against another - but not the putative Prime Ministers.

Earlier in the summer, the issue came to the fore after Lord Mandelson appeared to suggest that Gordon Brown wouldn't have a problem with a TV debate between the party leaders.

And now Sky News has started a campaign to get all three main party leaders to participate in such a debate during the next general election campaign.

Despite previous attempts by various broadcasters to make it happen In the past, the stumbling block has generally been that whoever feels they have least to gain from such an encounter has refused to co-operate, thereby ensuring that the whole project got pulled.

But Sky has made clear that the debate will happen, with any leader refusing to take part being "empty chaired". As Sky News boss John Ryley makes clear in his letter to the leaders: "Sky News is offering to work with those party leaders that want to take part, even if not all agree". 

Unsurprisingly, given his previous public backing for such a debate, David Cameron was quick off the mark to be the first to agree to Sky's proposal, stating in his letter accepting the terms:

"We urgently need to reinvigorate our political system - and holding a live television debate between the party leaders would be one important way of doing just that."

"The case for a televised debate is compelling: it would engage the public, help answer their questions, and bring a General Election alive."

"Prime Minister's Questions in the House of Commons are no substitute for a proper primetime studio debate. People want more than the brief exchange of questions they get at Wednesday lunchtime. They want to see the leaders of the main political parties talking in detail about the issues that matter to them, setting out the policies on offer, and opening themselves up to public scrutiny.

"At the next General Election, people are going to face a huge choice about the future of our country. They want politicians to be clear about where they stand. A full-length television debate has a big part to play in providing this and I look forward to working with you to make it happen."

If you want to show your support for Sky News's campaign, you can sign their e-petition here.

And below are two videos: Firstly, Sky News's Adam Boulton making the case for a debate and below that, the latest report from Sky's political correspondent Joey Jones outlining the terms of the debate and including news of David Cameron's agreement to them.

Jonathan Isaby