IN her first major speech since heading the SNP's campain for independence, Nicola Sturgeon yesterday set out to appeal to minds rather than hearts.

The chief benefit of an independent Scotland as envisioned by the Deputy First Minister is that it will enable the country to be run on principles of social justice.

With a commitment to work together with representatives from across political parties and civic Scotland, this was an appeal to centre-left, particularly Labour, voters. It included a tribute to Donald Dewar and carefully distanced independence from Braveheart ideas of national identity.

In addition to the political olive branch, there was a welcome recognition of the need for a new emphasis on policy before the vote. The promised papers and White Paper will have to provide considerable detail, however, if a majority of those voters who are currently undecided are to be persuaded to vote Yes. Two years before the referendum, polls suggest support for independence is declining. That fall has coincided with uncertainty about an independent Scotland's relationship with international bodies and, in particular, whether it could expect to be an immediate member of the EU and Nato.

Scheduling the referendum for 2014 has been attacked as a political move to benefit from a groundswell of national pride inspired by the 700th anniversary of the Battle of Bannockburn and Scotland's hosting of the Commonwealth Games and Ryder Cup and so may prove to be a double-edged sword. If the sporting events are as successful as the London Olympics, and especially if Scots athletes and golfers do well, however, confidence in Scotland is likely to rise. However, a report yesterday predicting Scotland's growth will be just 0.7% next year compared with 1.2% for the UK provided a timely reminder that the economy, the unemployment rate and the visible achievement of manifesto pledges will be the deciding factors in the referendum.

As Health Secretary from 2007 until this autumn, Ms Sturgeon has gained a considerable reputation for competence. The only blot on her copybook was two years ago when she wrote to a sheriff asking that a constituent who was a convicted social security fraudster be spared jail for a second offence. With a perfectly-pitched apology and admission of error to the Scottish Parliament, however, she improved her standing, not least because she did so despite having the backing of Alex Salmond for her action on behalf of a constituent. It was a defining moment in her relationship with the First Minister and an illustration that her strengths are very different from those of the party leader.

Ms Sturgeon demonstrated these qualities again yesterday in a forward-looking speech whose hallmark was an inclusiveness that will be a challenge to opposition parties. But she will have to provide a more detailed route map before voters have the confidence to take what is at present a leap into the unknown.