Guide to the Gers report

THE Gers report - or Government Expenditure and Revenue in Scotland - has been a staple of the Scottish political calendar for the past 17 years and can always be guaranteed to fan the flames of the unionist-nationalist debate.

The central idea is to provide the best estimates possible of Scotland's fiscal accounts, adding up all the tax and revenue collected in Scotland, alongside all the money spent north of the Border by the Scottish and UK governments. An estimate of whether Scotland is in surplus or deficit is provided. The report also includes different scenarios - so, for example, providing figures for revenue both with and without the substantial tax cheque received every year from the North Sea.

Figures come largely from the UK Treasury, although the final figures are the work of the Scottish Government's Chief Economic Adviser.