In February 2012 the Prime Minister delivered a speech in Edinburgh.

"I am a Unionist, head, heart and soul," he intoned, later adding that the United Kingdom was "not just some sort of deal, to be reduced to the lowest common denominator". It was, he admitted, an ostentatiously "emotional" pitch in favour of the constitutional status quo; with certain qualifications.

It ended with a Delphic allusion to "looking at how the devolved settlement can be improved further". In the two years since, David Cameron has retreated somewhat from following that through to its logical conclusion (though proposals from the Scottish Conservative Party are due by May) but, for what it's worth, I think he does the "heart" stuff much better than that relating to the "head".

Last Friday's oration in Stratford not only reads extremely well but it was also intended by Downing Street as a companion piece to the Prime Minister's Edinburgh speech a couple of years ago; indeed it explored many of the same themes.

It was also a realistic assessment of attitudes towards Scotland in the rest of the UK, from "quiet patriots" to "shoulder shruggers" who don't much care what happens in September. The Prime Minister also sought to reclaim Alex Salmond's "social union" as his own, arguing that, while the "intricate tapestry" of the UK wouldn't disappear with independence it was nevertheless "eased and strengthened" by the UK's institutional frameworks.

It was good, eloquent stuff. Mr Cameron suggested the "quiet patriots" were those who "love" the UK, "love our flag and our history", having earlier said the "best thing" about the Olympics hadn't been the winning but "the red, the white, the blue". This is like a red rag to some pro-independence bulls, for talk of the Union flag awakens something primordial in even the most civic of Nationalists.

"Shameful" was Nicola Sturgeon's response: the Prime Minister was "politicising" a sporting event for cynical political ends. Laying aside the obvious irony (anyone for tennis?), it was telling that the Deputy First Minister didn't attempt to rebut the substance of what was said, merely that it was being said at all, and in London too, a city which also provokes a Pavlovian response in certain supporters of independence.

Not to be outdone, the First Minister followed this up with an attack on Mr Cameron's "threadbare defence" of the Union, later telling STV such "flimsy" edicts were delivered from "on high, from Mount Olympus". If Scotland voted No, he added, it would "get taken to the cleaners by George Osborne and the London Treasury". Speaking from the recently hollowed-out Yes Scotland HQ, Blair Jenkins accused Mr Cameron of seeking to "lecture" Scotland, while the pro-independence columnist George Kerevan (betraying his Marxist provenance) condemned the speech as "imperialist".

All of this was delivered in a positive and non-scaremongering way (not), while the emerging SNP narrative about "elites" versus the "people" got another outing, a curious tack for a First Minister who, whether he likes it or not, is also a member of the political "elite" and has been for almost half of his life. As usual, Mr Cameron cannot win: make a speech in Scotland and he's "interfering"; make one in London and he betrays his "cowardice". I can't help feeling such histrionics indicate Mr Cameron's unashamedly emotional pitch for the UK discomfits Nationalists as it's much harder to rebut than dry, technical papers on currency unions and EU membership.

Their response also reeked of pandering to an element of the pro-independence movement, ubiquitous on Twitter, that seethes at the very mention of the Union, its flag, history and institutions, many of which, paradoxically, the Scottish Government seeks to preserve.

If ever the Prime and First Ministers did come face to face in televised debate it would be interesting to see Mr Salmond's reaction to such warm declarations from Mr Cameron. Would he laugh? Mock? Say it isn't so? Even a gentle put down would, I suspect, appear churlish. Again, not to those who have intended to vote Yes since before the debate began, but for the rest who stubbornly retain affection for aspects of Britishness.

Interestingly, the Prime Minister acknowledged the UK could be "a reticent nation", with a feeling that it was "vulgar to fly the flag". Some, he claimed, had advised him not get "too sentimental about the UK". "But frankly," he said, "I care too much to stay out of it. This is personal." Again, I can see no reasonable basis for doubting Mr Cameron's sincerity when it comes to this sort of sentiment.

In his STV interview, meanwhile, the First Minister couldn't resist indulging in his favourite insult: comparing someone with the last Prime Minister but one. "He doesn't do emotion particularly well," Mr Salmond said of Mr Cameron. "He certainly doesn't do it as well as Tony Blair used to be able to put it on." There was a contradiction, the implication being that a more convincing performance from Mr Cameron might have passed muster in Nationalist eyes.

Unlike Mr Blair, the Prime Minister has generally been pitch-perfect during his northern forays, not least two years ago. As one minister told me a while back, such interventions seek to contextualise Mr Cameron within the Scottish debate (something generally acknowledged as tricky) by saying: "Look, I'm one voice and yes, even though I'm English and posh, I still care."

For that to work, it needs to be a sustained assault, not a solitary salvo, and I'm told Mr Cameron's speech was the precursor to "bigger moves" on the rest of the UK front. Unionists freely admit they've pinched this strategy from the Canadian federalists in 1995, while taking care to avoid appearing panicked and tokenistic. Scottish Tory leader Ruth Davidson will keep the ball rolling with a speech on the "Union revived" later this week.

I've long thought Better Together needs a stronger spiritual pitch to complement its (often over-egged) critique of the practical consequences of independence. In the House of Commons last week the Labour frontbencher Gregg McClymont riffed on Alex Salmond's line about the English losing a "surly lodger" and gaining a "guid neighbour". How, he asked, could Scotland be a lodger in its own house?

"We built this house together," he continued. It "has, of course, been refurbished; it is not unchanging …but the fact is that this is our house as well as that of the other peoples of the United Kingdom".

Mr Cameron used a similar refrain the following day, talking of a UK built together: "Scotland, England, Wales, Northern Ireland. Brick by brick. This is our home, and I could not bear to see it torn apart."

Now it isn't perfect, perhaps even a little schmaltzy, but at least it's a start. Last month Lord Lang speculated that post-September, assuming a No vote, it would be necessary to "sing a song" of the Union and its benefits. Why on earth don't they start now?