BETTER Together has made an informal complaint to the BBC about the composition of the live audience at Monday's debate between Alex Salmond and Alistair Darling.

A selected cross-section of voters was invited to watch the campaign figureheads go head-to-head at Kelvingrove Art Gallery and Museum.

But the 200-strong audience appeared more sympathetic to Mr Salmond, giving the First Minister vociferous support at every stage of the debate.

At one point Mr Darling, the Better Together campaign leader, was left visibly rattled when an audience member launched an angry tirade against him, accusing him of privatising the health service, branding him a hypocrite and shouting: "Don't believe a word coming out of his mouth."

Among 13 questions from the audience put to Mr Salmond and Mr Darling during the 90-minute encounter, Better Together counted 10 from Yes supporters and three from No voters.

A Better Together insider said: "We have made our views known. It looks like the BBC did not have a grip on the make up of the audience or the questions from the floor."

Despite their complaints, No camp strategists privately admitted Mr Salmond came out on top.

However, they insisted his performance, while delighting Yes supporters, would fail to sway undecided voters.

The debate was watched by more than 800,000 viewers in Scotland on BBC1 and by 4.8million people on BBC2 and across a range of platforms across the UK.

The BBC said the audience was balanced between Yes and No voters with a smaller proportion - understood to be 20 per cent of the total - made up of undecided voters.

A spokesman said: "The format - including how the audience would be selected - was set out in advance and agreed by both campaigns."

The spokesman added: "The moderator, Glenn Campbell, made it clear in his introduction to those in Kelvingrove that it was a balanced audience and that all sides had to participate to make it feel as such to the television audience at home."