Prime Minister David Cameron "is right to be nervous" about the Scottish independence referendum, according to Alex Salmond.

The referendum is "the most empowering story in history", the SNP leader said yesterday.

Mr Salmond repeated his challenge for a ­televised debate with the Prime Minister, insisting Better Together leader Alistair Darling has now "withdrawn from the campaign" by refusing to do any more TV debates.

Yesterday, Mr Cameron admitted he is "nervous" about the referendum, after the results of the first poll since a second televised debate showed the No campaign's lead cut in half to just six points.

Mr Salmond said: "He's right to be nervous, because on the official polls the Yes vote is 48 per cent and rising. A huge number, hundreds of thousands of Labour supporters, are now supporting Yes."