Alistair Darling says yes to unionists' 'Not The Yes' campaign

Former Labour Chancellor, Alistair Darling (David Sandison)

Alistair Darling, the former Labour Chancellor, will kickstart the official campaign against Scottish independence in the next fortnight in an attempt to halt the momentum built up by Alex Salmond and the Nationalists since their victory in the Scottish elections last year.

Mr Darling has agreed to become the leading figure in the unionist campaign, but it is understood that for the launch he will share a platform with the former Liberal Democrat leader, Charles Kennedy, and the former Scottish Conservative Leader, Annabel Goldie. With days to go, a name for the campaign has still not been settled.

With Mr Salmond having already grabbed the "Yes" title for the pro-independence lobby, some unionists believe they have no option but to choose "No" as a clear way of setting themselves apart from the Nationalists. But there is also a feeling in the unionist camp that "No" is not positive enough and that the pro-United Kingdom campaign must be seen to be in favour of something, rather than just against independence.

Michael Moore, the Scottish Secretary, told The Independent: "The key thing is that we are the positive case for Scotland staying in the UK as well as challenging those who wish Scotland to separate away. You will see a new dimension to the campaign."

Mr Darling is widely respected in Scotland and, as a Labour politician, is exactly what the unionist camp needs if it is to make sure that wavering Labour voters do not drift over to the nationalist side. He is aware of the size of the challenge facing the unionists in what will be a long run-in to the referendum in 2014.

Even though support for leaving the UK languishes at about 33 per cent in many polls, that figure rises dramatically when the SNP's preferred choice of wording, asking simply if the voter agrees that Scotland should be independent, is used.