The Scottish National Party yesterday demanded that Ofcom reverse the “undemocratic and illogical” decision not to list it as a “major UK party” for general election broadcasts.

SNP’s Westminster leader Angus Robertson MP said the exclusion of his party would cause a “democratic deficit in broadcasting” for the general election.

He said: “Ofcom has excluded the SNP from its list of ‘major UK parties’ even as a basis for consultation, while consulting about parties with far fewer MPs than the SNP has.

“That is quite simply undemocratic and illogical, and it should be unacceptable to any democrat, as it simply doesn’t reflect the reality of politics across the UK today.”

Ofcom’s list of major parties recognises the SNP as “a major party in Scotland” rather than in the UK.

An Ofcom spokeswoman said: “This is based on its past election performances, current opinion polling in Scotland and the fact the SNP does not field candidates across other countries of the UK.”

The communications watchdog requires that relevant broadcasters allocate at least two party election broadcasts to each “major party” ahead of an election.

The Conservatives, Labour and the Liberal Democrats are on the existing list of major parties in the UK and Ofcom is consulting on whether parties such as the Greens and Ukip should be included.

The initial view of the regulator is that Ukip may qualify for major party status in England and Wales for the general election.

It comes as the wider debate on what parties should feature on televised leaders’ debates snowballed over the weekend.

Labour leader Ed Miliband yesterday accused David Cameron of “running scared” of the debates after the Prime Minister said he would refuse to take part if the format included Ukip leader Nigel Farage but not Green Party head Natalie Bennett.

Under plans put forward by the major broadcasters in October, Mr Cameron would take on Mr Miliband alone in one debate, with another featuring the three mainstream party leaders and a third also including Mr Farage.

Mr Miliband said: “I want these debates to happen, I think they should happen with David Cameron or without David Cameron. If an empty chair represents David Cameron in these debates, so be it.