IT was, said David Cameron, “a significant day for devolution” and a “major milestone in delivering a powerhouse parliament for Scotland”.

The Prime Minister’s statement that the fiscal framework underpinning Holyrood new powers had, after months of tortured negotiations, finally been agreed emerged on February 23.

The message was trumpeted from one end of Whitehall to the other: the mythical 'Vow' had finally been delivered.

So there can be little doubt that Cameron’s Downing Street neighbour heard it.

Yet as we reveal today, George Osborne evidently did not consider the matter closed.

Three weeks later, the Treasury raised an objection to the deal’s technical annex and Osborne refused to sign off on the financial architecture of the Scotland Bill.

This last minute veto was as astonishing as it was reckless.

A critical Holyrood vote was almost cancelled, something which could easily have created a constitutional crisis and changed the context of the Scottish election.

Given the sums involved - £200m is not going to break the Treasury - it appears to have been brinkmanship for its own sake, some political sport to test and tweak the SNP.

But if Osborne had got his way, it would have caused a real detriment to the Scotland budget.

To her credit, the First Minister refused to blink and he backed down.

Osborne’s behaviour was a classic example of perfidy on devolution.

It shows that rather than being joyously “delivered”, the Vow had to be forcefully extracted from Westminster, and we should not forget it.