David Cameron, Ed Miliband and Nick Clegg have pledged to keep the Barnett Formula in the event of a No vote in the Scottish referendum.
But what is it?
- The Barnett Formula has been used to distribute public money between England, Scotland, Wales and Northern Ireland
- Population shares and changes in spending will automatically be reflected in the amount allocated to devolved administrations
- It was initially designed by former Chief Secretary to the Treasury Lord Barnett as a temporary measure but has lasted more than 30 years
- Critics of the system argue that Scotland is allowed to spend a greater amount on services per person than in England
One story dominates Thursday's front pages with some newspapers printing emotive pleas to voters to keep the United Kingdom as one.
In Edinburgh tonight you can hear it and feel it. The buzz, the banter of the day and the thrilling sense something big is coming tomorrow.
There is nervousness, anxiety and on the streets of Edinburgh fuelled by an atmosphere unlike anything seen before in recent UK politics.