22/01/2015 11:37 GMT | Updated 22/01/2015 11:59 GMT

Broadcasters Call Cameron's TV Debate Bluff, Invite Green Party

AFP via Getty Images
British opposition Conservative party leader, David Cameron (L), shakes hands with opposition Liberal Democrat leader, Nick Clegg (C), and Prime Minister, and leader of the ruling Labour Party, Gordon Brown (R), at the end of the live televised debate, at the University of Birmingham, in Birmingham, central England on April 29, 2010. Britain's main party leaders squared up for the final pre-election TV debate Thursday. AFP PHOTO/Gareth Fuller/Pool (Photo credit should read GARETH FULLER/AFP/Getty Images)

The Green Party, SNP and Plaid Cymru have all been invited to take part in the televised election debates, after broadcasters revised their proposals in order to persuade the prime minister to take part.

The broadcasters has initially suggested three debates. One would have featured David Cameron, Ed Miliband, Nick Clegg and Nigel Farage. The second would have included Cameron, Miliband and Clegg and the third would have been a Miliband and Cameron head-to-head.

The new proposal from the broadcasters is a 7-7-2 format rather than the initial 4-3-2. It would see the BBC and ITV each host a debate featuring the Tories, Labour, LibDems, Greens, Ukip, SNP and Plaid Cymru.

Sky and Channel 4 would then host a Cameron v Miliband head-to-head.

Cameron had said he would refuse to take part in the debates unless the Green Party leader Natalie Bennett was invited.

Critics argued that rather than finding some new found love for the Greens, Cameron was using their exclusion as an excuse to dodge the debates all together.

Conservatives argued it was unfair that Farage, who is seen as a threat to the Tory vote, was included whereas Bennett, who is a threat to Labour, was not.

The new plan will delight the Green Party, which has been lobbying hard to get Bennett into the debates. It is also a coup for SNP leader Nicola Sturgeon and Plaid Cymru's Leanne Wood.

The previous plan included a repeat of the 2010 debates, that saw a three-way debate with Labour, the Conservatives and the Lib Dems.

Arguably the biggest loser from the 7-7-2 format would be Clegg. Sharing the platform with just Cameron and Miliband would give the deputy prime minister the chance to portray himself as the centrist candidate. However this message will be diluted if he is joined by Farage, Bennett, Sturgeon and Wood.

The suggested schedule for the three debates is 2 April, 16 April and 30 April. The election is on 7 May.