Yes or no? Day of decision comes closer for Scots

David Cameron and Alex Salmond will today sign off on a historic deal to hold a single question referendum on whether Scotland should remain in the United Kingdom (PA)

David Cameron and Alex Salmond will today sign a historic deal to hold a single-question referendum on whether Scotland should remain in the United Kingdom.

Under plans to be formally agreed by the Prime Minister and First Minister at a meeting in Edinburgh, voters will be asked a single yes/no question in the independence plebiscite which will be open to all Scottish voters aged 16 or over.

The deal signals the start of a marathon campaign ahead of the vote, which will be held in the autumn of 2014. "This marks the beginning of an important chapter in Scotland's story and allows the real debate to begin," Mr Cameron is expected to say.

"It paves the way so that the biggest question of all can be settled: aseparate Scotland or a United Kingdom? I will be making a very positive argument for our United Kingdom."

The latest polls on independence suggest that support for leaving the UK has dropped, with 53 per cent backing the status quo and 28 per cent in favour of an independent Scotland. But SNP strategists are confident that the polls will narrow as they lay out their plans. They also expect to win support from 16 and 17-year-old voters.

"The game has changed considerably in the past couple of weeks," SNP deputy leader Nicola Sturgeon said yesterday. "The good thing about getting the process issues out of the way is that we can get on to that substantive debate about why Scotland would be better as an independent country."

Former Chancellor Alistair Darling, who is leading the cross-party Better Together campaign, said: "The key thing at stake in these negotiations was to get the single question," he told the Sunday Politics programme. "I would have preferred to have had this referendum in the autumn of 2013 because frankly a two-year election campaign is going to try the patience of the public, never mind the politicians and those who write about it."

The Liberal Democrat Scottish Secretary, Michael Moore, said: "I believe it will now allow us to put up in lights the big issues about the big debate on what is best for Scotland."