Image copyright Reuters Image caption Better Together head Alistair Darling and Scottish First Minister Alex Salmond went head to head in two TV debates before the independence referendum

The SNP has welcomed a public consultation to be held by the BBC on its coverage in the lead-up to next year's general election.

It came after the party strongly criticised its exclusion from three nationally-televised debates ahead of the vote.

A consultation on the BBC's election guidelines will begin next week.

The SNP predicted there would be "substantial backing" for the party's inclusion in TV debates.

In its response to call by Nicola Sturgeon for the SNP to be allowed to take part in the debates, a BBC spokesman said on Friday that the broadcaster made "editorial judgements about coverage during the general election campaign informed by evidence of past and current electoral support".

He added that the BBC Trust would be launching a public consultation on the "relevant guidelines" next week.

'Surge in support'

But a spokeswoman for the BBC Trust clarified on Saturday evening that the body will hold a public consultation on its draft election guidelines, and not specifically around the line-up of the TV debates.

Speaking ahead of the clarification, SNP MSP Stewart Maxwell said: "With the SNP now the third largest party in the UK by some considerable distance and two opinion polls this week showing a surge in support, it would be utterly unacceptable for the broadcasters to exclude the SNP from coming TV debates.

"The announcement that the BBC Trust is to launch a public consultation on this issue is a welcome one.

"It will give people the opportunity to make their views known to the BBC and I have no doubt that there will be extensive backing for including the SNP in these debates.

"Broadcasters have a duty to be impartial in their election coverage and it would be a gross failure in those democratic duties if the SNP were excluded."

Image caption David Cameron, Nick Clegg and Gordon Brown took part in televised debates ahead of the 2010 general election

Last month, the BBC, ITV, Sky and Channel 4 announced plans for a total of three nationally-televised debates ahead of May's general election.

UKIP leader Nigel Farage has been been invited to take part in one of the debates alongside David Cameron, Ed Miliband and Nick Clegg.

A second debate would see Mr Cameron and Mr Miliband go head-to-head, with a third debate seeing the Conservative and Labour leaders being joined by Mr Clegg.

But the SNP, Plaid Cymru and Greens would not be included in any of the debates under the current proposals.

Instead, the leaders of the four largest parties in the Scottish Parliament are to be invited to take part in a peak time debate on BBC One Scotland, which would also be made available across the UK.

However, the Scottish Greens would not be included despite having two MSPs at Holyrood. A third MSP, John Finnie, announced last month that he had joined the party but said he would continue as an independent member of the parliament until the next election in 2016.

'Duty of impartiality'

Two polls published on Thursday suggested the SNP was on course to massively increase its number of MPs at Westminster in May's election.

An Ipsos/Mori poll for broadcaster STV suggested that 52% of Scots would vote for the SNP if there was a Westminster election tomorrow, which it said would see the party increase its number of seats from six to 54.

A YouGov poll for The Times put the SNP on 43%, which it said would give them 47 seats.

The SNP's membership has also trebled to more than 83,000 since September's independence referendum, making it the UK's third largest political party with about twice as many members as both the Liberal Democrats and UKIP.

Addressing a rally of new SNP members in Dumfries on Friday evening, Ms Sturgeon - who will become SNP leader and Scotland's first minister in November - said the polls "put beyond any doubt" that excluding the SNP from the prime ministerial debates was "unacceptable".

Ms Sturgeon also told the broadcasters that "it would be a failure in your duty of impartiality" if the debates went ahead as currently planned.

She added: "I want to send a direct message to the BBC, ITV, Sky and Channel 4. To exclude, not just the SNP, but also the Greens and Plaid Cymru, would be to wilfully ignore the reality of the political landscape that exists, not just in Scotland, but across the UK."

In its response to Ms Sturgeon's comments, the BBC said: "We make editorial judgements about coverage during the general election campaign informed by evidence of past and current electoral support.

"Opinion polls are part of that evidence whereby we take account of consistent and robust trends across different polls over time, rather than reacting to individual polls.

"We have also said that we will continue to look at any further evidence of changes in electoral support as we get closer to the election campaign. The BBC Trust will be launching a public consultation on the relevant guidelines next week."