The UK’s Conservative Prime Minister David Cameron is expected to offer Scots the power to raise all income tax in Scotland, if they reject independence at the referendum planned for September. This would make the Scottish Parliament responsible for raising 40% of the revenue it spends, and would be offset by and equivalent cut in the block grant that Scotland receives from the Treasury.

This is a change that should have happened years ago. Critics call the present arrangement a ‘pocket-money parliament’. Its only debate is how to spend the money gratuitously handed down to it by its English parent.

If Scotland had to raise much of its own revenue, however, the debate would change. The discussion would go beyond how to spend money, and embrace the question of how to raise it. There would, for the first time, be a national discussion about how much Scotland should be spending on its government. Taxpayers, both individuals and businesses, would start raising questions about value for money.

That should be good news for Mr Cameron. At last his Conservative Party, presently sidelined and bereft in Scotland and down to just one Conservative MP in Scotland – would have a real role once again. It would become a home for all those who believe that spending is too high, and who resent paying to fund a profligate government.