GORDON Brown yesterday waded into the row over the SNP Government's credibility, accusing it of asking voters to put their cross next to "a blank page" in the independence referendum.

The former Labour Prime Minister said the lack of legal advice on Scottish membership of the EU showed the Nationalists would try to hide the truth about the impact of leaving the UK.

In a speech in his Kirkcaldy constituency, Brown said the Union was a force for greater social justice and listed 20 questions on the economy, defence, the monarchy, pensions and welfare he said SNP ministers had yet to answer.

Alex Salmond has promised a white paper on the mechanics of independence in November 2013, but Brown said the public needed information sooner.

He said: "I call it 'blank page' nationalism, hiding the truth about the costs and risks of independence. The SNP have decided not to tell the full truth, not just about what happens to our membership of the EU and the euro, but about what happens to interest rates, mortgages, money supply and inflation, to pensions, to child benefit, to the minimum wage, and even to the armed forces, citizenship, and the monarchy in their plans for a separate state.

"How, when your entire future is at stake, can you put a cross next to a blank page? How, when you are voting for your children's future, can you put a cross next to a party hiding the truth?"

But Kirkcaldy SNP MSP David Torrance said inequality had increased in Scotland under Brown, undermining his case for the Union.

He said: "The question Labour need to answer is why they want the key powers over jobs, the economy and welfare to be held by a Tory-led government at Westminster which is delivering inequality – rather than by the Scottish Parliament which is 100% accountable to the people of Scotland and committed to fairness."

Salmond's difficulties over Europe have seen his critics swarming to attack him in recent days. Former Labour foreign secretary David Miliband claimed the SNP's case that an independent Scotland would have automatic EU entry belonged on "fantasy island".

The European Commission last month offered to give its view on the subject if the UK, as the relevant member state, presented a detailed scenario. But Westminster, which says its legal advice is clear that Scotland would have to apply as a new country, refused to take up the offer.