AFTER the lovebombing last week by David Cameron, his chancellor George Osborne travelled north to revel in his role as bad cop.

As Dirty Harry he carried a very large gun to shoot down Alex Salmond's plan to share the pound after independence, but the bullets were crafted by the longstanding Permanent Secretary to the Treasury, Sir Nicholas Macpherson.

Mr Osborne had with him a 76-page Scotland Analysis document, impenetrable to those of us without a PhD.

The Chancellor read out a 19-page speech based on its contents. But the real killer was a memo running to just over two pages by the top civil servant at the Treasury, Sir Nicholas Macpherson.

Nick, as he styles himself, penned a devastating critique of currency union in refreshingly lay language, but with characteristic Treasury arrogance that hinted only his department could ever run an economy, and certainly not pipsqueaks at St Andrew's House.

In fairness, the Treasury don't just sneer at Scots. They sneer at other Whitehall departments. But Sir Nick's words were gold dust for the Chancellor.

As a result Mr Osborne gave the impression of a card-player with a terrific concealed hand. In other words, he was even more than usually objectionable in his arrogant smugness.

The venue for the declaration, stacked with around 70 business types, was a dramatic penthouse with a panorama of Edinburgh Castle, Union flag fluttering, in the appropriately named Bread Street. Treasury dudes appeared blind to the coolness of this address.

Mr Osborne talked about "the pound in your pocket," the phrase coined by Harold Wilson in 1967 as he was forced into devaluation by a crippling national debt of £800 million. The UK national debt now stands at £1.16 trillion.

From the airy penthouse journalists were led down to a cold, barely lit basement for a briefing with the Chancellor and sight of the Macpherson memo. Maybe they were trying to create an echo of All the President's Men.

Whatever the venue, Mr Osborne was saying to Alex Salmond: "Do you feel lucky, punk?"