SEVEN party leaders will jostle for position in two of the three TV debates, broadcasters announced yesterday in a dramatic U-turn.

New additions to the televised debates are Green Party leader Natalie Bennett, Plaid Cymru leader Leanne Wood and SNP leader and Scottish First Minister Nicola Sturgeon.

A jubilant Ms Bennett last night proclaimed that the decision marked the “Green Spring.”

The news follows uproar over her exclusion from the process despite the Greens polling ahead of the Lib Dems in several recent surveys.

The three new debaters will join Tory Prime Minister David Cameron, Lib Dem deputy PM Nick Clegg, Labour leader Ed Miliband and Ukip chief Nigel Farage in the pandemonium debates for the BBC and ITV.

These will be followed by a final tete-a-tete between Mr Cameron and Mr Miliband hosted jointly by Channel 4 and Sky.

Broadcasters yesterday threatened to “empty chair” any party leader who refuses to take part.

The TV channels had originally announced plans for one debate to include Mr Clegg and Mr Farage and one to include Mr Clegg, in addition to the Labour and Conservative leaders.

But earlier this month Mr Cameron said he would refuse to take part unless the Greens were included — in what was seen as a cynical move to split the Labour vote.

In a joint statement, the BBC, ITV, Channel 4 and Sky said they had “continued to monitor the electoral landscape” since making their initial decision.

Ms Bennett said: “The decision to include the Greens in two debates is an acceptance by the broadcasters that we now are in an age of multi-party politics.

“This groundbreaking decision serves the interests of both the electorate and British democracy. Our membership and polling surge demonstrates that when people hear about Green Party values and policies many embrace them.”

But Sinn Fein, which currently has five abstentionist MPs, said it would challenge the decision.

Democratic Unionist Party leader Peter Robinson branded his own exclusion “unacceptable.”

And Lib Dem spokesman bemoaned the exclusion of Mr Clegg from the final debate.

“We have always been clear that as a party of government, we must be able to defend our record in all the TV debates,” he said.