On Monday, the UK cabinet assembles in Aberdeen, where David Cameron is expected to predict a glittering future for the oil industry within a united kingdom. Meanwhile, the Scottish cabinet assembles in Aberdeenshire, where Alex Salmond is expected to promise a glittering future for the oil industry in an independent Scotland.

Welcome to the surreal world of the referendum campaign. And to the parallel world of the UK's other coalition, where Labour, Tories and Lib Dems have united to sell the Better Together unionist campaign and sink the SNP and its Green and Scottish Socialist allies in Yes Scotland.

Examine the photographic archive since the rival campaigns were set up and some arresting images litter the album. Alistair Darling sharing a cheery balcony photo op with Scots Tory leader Ruth Davidson; George Osborne and Ed Balls grinning amiably at each other on Andrew Marr's Sunday sofa.

Yet just as that Cameron and Clegg romance born in the No 10 rose garden has seen the early ardour cool, so too have the no campaign alliances begun to fray round the edges. A series of polls showing support for yes rising – much of it emerging from the erstwhile undecideds – has evidently shredded a few Better Together nerves.

Better Together never were natural bedfellows. For many on the Scottish left, making common cause with the Conservatives – a party with just one Westminster MP – was always a political bridge too far. The sight of Alistair Darling winning plaudits at a Tory Scottish conference caused something of a run on the sick-bag market.

With the public backing of a certain Gordon Brown, United with Labour was launched; unionist, but strictly lefty with it. It is fuelled by solidarity with other Labour foot soldiers in England and Wales, and often by a visceral loathing of the SNP. For in Scotland, perversely, the most bitter tribal battles are nationalists versus socialists, parties between which neutral observers would find difficulty inserting an ideological cigarette paper.

That divide also explains the rise of yet another splinter group, Labour for Independence, populated by left-leaning yes voters who fret that Yes Scotland harbours too many Nats for their taste.

Scottish trade unions have also been resistant to back the Labour leadership's referendum stance. Last week the Scottish Trades Union Congress published a paper, A Just Scotland, asking policy questions of both camps but declining to endorse either. And on Saturday the Public and Commercial Services Union, representing 30,000 civil servants, held a conference at which it too plumped to stay neutral, although 20% argued for backing yes and none for no.

Meanwhile, the Lib Dems have embarked on a second commission to determine the best options should there be a majority no vote. Given their commitment to federalism, some of their Scottish members are more than a little irritated with gung-ho-for-no colleagues in Westminster.

And it is the prospective offers from the three unionist parties that is causing the most head scratching in their ranks. However much they may trash the SNP's independence white paper, they're acutely aware that just flying the flag for the status quo won't cut it. Nor vague promises of something better whenever. That was the Alec Douglas-Home's line in 1979, and a second bite at the referendum cherry took 20 weary years. The Scottish electorate tends to have a long memory of such affairs.

Meanwhile the tactic dubbed Project Fear seems to be repelling as many as it scares.

But here's the rub. The three parties can't come up with a joint package. Not without a self-defeating public bunfight. So their looming spring conferences are set to launch a bidding war.

The Scottish Tories, once reluctant to support devolution in any form, have recanted. Not least in the face of a new Conservative group styling itself Wealthy Nation, plighting its troth to yes and aiming for a stronger right-of-centre in an independent nation.

Scottish Labour is fighting an internal battle between those opposed to fiscal autonomy and those who believe some kind of "devo max" is essential to save their own electoral bacon. The hardliners, unsurprisingly, include most of the Scottish Westminster MPs who would be jobless in the event of a yes vote.

Amidst all which confusion there is but one certainty. Ukip is entirely irrelevant. And sae the Lord be thankit.