It now seems clear that for all the talk of positivity from both sides of the independence debate, three elements and the extent of their impact will decide the outcome of the referendum.

Having lovebombed Scotland with talk of the British social union that expands across Hadrian's Wall and how pooling resources and sharing risks strengthens the whole UK family, it seems clear the greater effect of the Coalition's approach will be on fearbombing Scotland or, as one Whitehall source graphically described it, employing the Dambusters' strategy.

It certainly appears the case that in the past few weeks the Scottish Government's defences have been bombarded; from Mark Carney's intervention to President Barroso's and from BP boss Bob Dudley's raising of "big uncertainties" to Standard Life chief David Nish's possible exit strategy.

But the denizens of SW1 believe it was the strike by Chancellor George Osborne, aided by Labour's Ed Balls and the Liberal Democrats' Danny Alexander, on rejecting a currency union that breached the SNP dam.

Yet it is one thing for the likes of Messrs Osborne, Balls and Alexander to raise doubts and fears but quite another when industry giants like BP and Standard Life do so - and the Nationalist triumvirate of Salmond, Sturgeon and Swinney knows it.

While the pro-UK approach has been strongly tilted towards highlighting the uncertainties of independence sparking the constant SNP accusation of scaremongering, the anti-UK approach has also had its negative side, raising fears and doubts about what happens if independence is rejected in the autumn.

One constant line has been that if there is a No vote, Scots can kiss goodbye to the idea of more powers for Holyrood even though it seems increasingly clear the momentum towards greater Scottish devolution appears unstoppable.

Earlier this week, Mr Swinney published analysis about what would happen if, in the event of a Yes vote, Westminster held its line on not having a currency union. This, he pointed out, would lead to those living south of the Border having an extra £130 billion of debt dumped on them, resulting in around £5bn a year in additional interest payments and equivalent to a penny on income tax.

Then, Mr Salmond argued that if a currency union were agreed between Edinburgh and London, the good folk of England, Wales and Northern Ireland would not have a say on such a matter through their own referendum.

The words land, cloud and cuckoo spring to mind. The idea that all three main Westminster parties, having firmly rejected a currency/monetary/banking union, then, after a Yes vote, suddenly cave in, blithely change their minds and agree to one without seeking the mandate of the people of the UK, is for the birds.

At times, Mr Salmond has given the appearance of King Canute, shouting louder and louder as the Whitehall waves inconveniently refuse to turn back and simply keep crashing down.

This level of bombardment from the pro-UK forces - and it will continue next week when Gordon Brown is expected to make a key intervention - will begin to take its toll unless the FM, if he is not to be consumed by the rising waters, begins to strike back hard - and soon.