Whether you believe that Scotland has given more cash to London since 1979 via taxes and oil and gas revenue than it has received back into its budget via the Scottish office, fully released figures will let you decide for yourself!

The SNP claim (probably correctly) that there has been a £34 billion surplus on paid by the Scots to London.

Figures from a recent academic study by Professor Alex Kemp of Aberdeen University. For the first time, Kemp has been able to establish precise figures for the revenues produced by the Scottish sector during the 1980s and early 1990s.

The SNP is also claiming that Scotland's share of Britain's national debt has been more than repaid since 1979.

They base this argument on a parliamentary answer by Patricia Hewitt, the financial chief secretary to the Treasury, which reveals that Scotland's share of the UK national debt in 1979 was £13 billion.

According to the SNP, Scotland paid £34 billion into the national coffers during the next 15 years while Britain increased its national debt by almost two-thirds, an increase of £270.3 billion. As a result, party strategists calculate that Scotland would not be liable to pay £2.5 billion annually of UK debt interest payments. The Scottish Office says that it would.