( CNN ) Back in 2010 Britain 's politicians broke new ground . They were long used to haranguing each other in the UK 's rowdy House of Commons -- but they 'd never had American style pre-election head-to-head debates . It is necessary and long-established political fare in the U.S. -- but over here in the UK , it was novel . It seemed to go well -- political points were scored , and polls were commissioned looking for advantages gained or lost . It was a drama of sorts , even though no knock-out punches were landed . Prime Minister David Cameron and his Conservative party won the election , but not by enough to go into government alone . For the past five years he 's been governing in coalition with the UK 's third party , the Liberal Democrats . And their leader , Deputy Prime Minister Nick Clegg , has mostly backed Cameron in Parliamentary debates against the opposition Labour leader Ed Miliband . Britain 's broadcasters , keen to channel lively politics onto prime time TV and boost ratings , have been working the corridors of power themselves over the past year to try to nail down a repeat -- or two -- of the 2010 knockabout . What 's at stake is n't just the proposed debates ahead of May 's general election -- but the enshrining of such debates permanently into Britain 's political architecture -- just like in the U.S . But while Cameron and Miliband have hired former White House election advisers to edge them in to the lead , no one can agree on what form a debate should take , how many there should be , or even who should be invited . Cameron has insisted on just one debate involving the leaders of seven leading UK parties -- giving equal airtime to the Greens , the Scottish Nationalists and the upstart rightwing UK Independence Party ( UKIP ) , among others . But Miliband 's Labour party is holding out for at least one head-to-head debate with Cameron . No one seems to be budging but both of the UK 's largest parties could use the bump in the polls such a debate might bring . Part of the problem is the British electorate , which has changed since 2010 , boosting the fortunes of some of the country 's former political outliers . The rightwing UKIP , which has pledged to take the UK out of the European Union , has made massive gains in the past year -- mostly at the expense of Cameron 's Conservatives . In Scotland , the September independence referendum ( which narrowly failed ) so reinvigorated the Scottish National Party that they could hit what is usually a key Labour stronghold , undermining Miliband 's bid for power . All of this has made the whole process of nailing down precisely who will be allowed in the debate that much more tortuous . For the big leaders who drive that conversation , it is about how each outlier can help them -- and hinder their rivals . It once looked like it would become as much of a British institution as rain , or fish and chips , but now the election debate seems in danger of not happening at all . On the upside , you can still tune in to House of Commons TV most days of the week to get your fix of one lawmaker bellowing at another . But do it soon -- I hear that even those everyday raucous exchanges are being scrutinized for being a bit old-fashioned .
Election TV debates only arrived in the UK in 2010 . Broadcasters are keen to repeat the head-to-head format in the run-up to the 2015 poll . But factional politics and arguments about who is invited may derail a TV debate .