It is no surprise that the latest opinion poll, published today, shows a majority of Scots would vote to remain in the UK if the referendum on independence were held tomorrow.

The results of the YouGov poll commissioned by Alistair Darling on behalf of the Unionist campaign are broadly in line with previous findings.

One-third answered yes and just over half said no to the question: in the referendum on whether Scotland should be a country independent of the rest of the UK, how would you vote? On their own these findings are not the stuff of headlines but announcing the results of this poll on the eve of the launch of SNP's campaign for a Yes vote in 2014 is a tactical move by the Unionist camp, signalling they are now warming up for the long campaign ahead. The numbers mark out the task facing the Nationalists if they are to convince the sizeable segment of the population thought to be open to persuasion that independence is the better option.

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The subsidiary questions in the poll are significant. One reveals the size of the task facing the SNP in showing 28% of those who voted for a Nationalist candidate at the Holyrood election last year would vote no to independence. The other shows there is another potential mountain to climb for the Yes campaign, on the economy: only 27% believed they would be better-off in an independent Scotland while 47% thought they would be worse-off.

With this poll, the No campaign, still in embryonic form although big political names including Gordon Brown, Charles Kennedy and possibly Tony Blair are increasingly mentioned, provides a timely reminder of the extent of polarised opinion and how much there is to play for. Regardless of which celebrities are unveiled today to add sparkle to the politics of the independence campaign, the measure of how much pace it gathers over the next 27 months will be the conversion rate of the undecided and those currently minded to vote no, and whether a majority believe independence will provide tangible economic benefits down to household level.

That will become more crucial as the fate of the eurozone's peripheral economies becomes known. Whether they stabilise and recover or leave the euro will help shape opinion about the effects of decoupling the Scottish economy from the UK in an increasingly global world.

Alex Salmond has earned his spurs for political adroitness but Mr Darling is also a canny operator and his experience at the eye of the financial storm has given him a solid credibility that will count for much as the debate ventures deeper into the impact of independence and consequences for UK institutions from the Post Office to the Foreign Office.

A growing impatience with entrenched positions is already evident in the public forums and both Yes and No campaigns must beware the danger of referendum fatigue. The involvement of heavy-hitting political figures is, we trust, a welcome sign of a new level of gravity that should bring necessary substance to the debate that will determine Scotland's future.