Alex Salmond takes TV debate fight to BBC Trust

• Alex Salmond: appeal. Picture: Getty

The SNP has written to the trust, the governing body set up to ensure that the public gets the best out of the BBC, after Salmond and Plaid Cymru's call for a debate featuring the Nationalist parties was rejected by the BBC's executive.

The letter, which will arrive on the trust's desk tomorrow, represents the SNP's last attempt to get the BBC to change its mind on the issue before the party resorts to legal action.

The appeal is supported by the Welsh Nationalists Plaid Cymru, who also believe that the Celtic nations should be represented in the debates during the election campaign.

"In appealing with Plaid Cymru to the BBC Trust – the guardians of the licence fee – we hope to finally get a fair hearing for the voters and viewers of Scotland and Wales," said Angus Robertson, the SNP's Westminster leader.

"It is clear that the cosy metropolitan machine of BBC executives and London parties, who agreed to cut Scotland out of these debates from day one, have no intention of allowing Scotland's voice to be heard.

"We are asking the trust to recognise immediately the urgency of this matter, the importance and exceptional circumstances of the case and to grant the SNP the chance to appear in person as soon as possible to appeal this decision."

Robertson added: "The trust … must review the actions of the BBC's management with a view to restoring fairness, balance and a voice for all nations of the UK – not just England – to the BBC's election coverage.

"The BBC's rejection of the proposed fourth debate is without reason or rationale and I hope the trust will recognise the sensible resolution offered by such a debate."

Under existing plans, this general election will see the leaders of the three main UK parties take part in three debates hosted by the BBC, Sky and ITV. The SNP and Plaid Cymru want a fourth debate that would pit their representatives against Brown, Cameron and Clegg.

The SNP's letter will suggest that their case should be heard at an oral hearing of the trust at the earliest available opportunity. It will point out that the BBC has refused to release details of the steps that it took to reach the current deal with the three main parties.

The SNP will suggest that the BBC's independence has been compromised because some of the terms of the debates were "dictated" by the main parties. It will also argue that the BBC charter lists "representing the UK, its nations, regions and communities" as one of its public purposes.

Opponents have argued that an SNP presence is not required because the Nationalists are not fielding candidates south of the Border and, therefore, Salmond has no chance of getting to Number 10 Downing Street.

David McLetchie, the Conservative Scottish campaign manager, said: "These are debates between the leaders of the UK parties who could become prime minister. This is a British general election to chose a British government in the British parliament. Alex Salmond isn't even standing.

"This is just pathetic attention seeking from Alex Salmond whose party is not at the races – the British general election. As it is, Alex Salmond will have three chances to debate here in Scotland against the Conservatives, Labour and the Lib Dems. But, remember, he is the man who twice refused to appear in TV leaders' debates in Scotland for the European election. It's time Alex Salmond got on with what he was elected to do, helping Scotland out of Labour's recession."

The BBC Trust declined to comment.