WHILE the powerbrokers of Whitehall still adopt a sanguine attitude towards the independence referendum - No 10 made clear, despite the narrowing polls, the strategy remains steady as she goes - unease is beginning to stalk the corridors of Westminster.
More and more politicians, particularly those within Labour, are privately voicing concerns that not enough is being done to win hearts and minds; the religion of independence has to be matched - and bettered - by the religion of the Union. And Labour, they insist, have to lead the UK charge.
Slowly the party seems to be waking up to the existential threat standing, elephant-like, on its doorstep: that if the Nationalists win on September 18, Labour's future will be altered dramatically.
A Yes vote would shake the political kaleidoscope north and south of the Border.
In Scotland, as the SNP hit a political high, the Labour leadership, having sided with the Tories and the LibDems, would be scrambling around looking for how to deal with the new reality.
In England, a splintered Labour force would, certainly post-2016, be put at an electoral disadvantage against the Conservatives, losing a number of talented Scottish politicians, from whose ranks it has in the past drawn many of its leading lights.
But, despite all the efforts of the Lib-Con alliance, it is Labour on the ground in Scotland that will save the Union, if it is to be saved.
As rumblings of disquiet about the leadership of the No campaign by ex-Chancellor Alistair Darling resurface in the wake of the crumbling anti-independence lead, who should make an appearance but his old Downing Street mucker Gordon Brown.
For many Scots, the former PM is still a mighty political figure, who has at last become engaged, enunciating a more positive message about the 300-year-old Union.
Not only that, but Ed Miliband will convene his Shadow Cabinet in Glasgow on Friday to make clear to Scottish voters that the core Labour values of creating social justice, fighting poverty and spreading prosperity can best be achieved, for Scots, within the bigger resourced UK than within a go-it-alone Scotland. Positivity, positivity, positivity.
As with most things in life timing is everything and the key to winning the referendum will be peaking at the right moment.
Rather than adopt the attitude, which behind closed doors seems to exist in Whitehall, that the referendum is already won, the pro-UK camp must, if it is indeed to win, assume it could lose the battle for Britain, and up its game.
And that means deploying every single tool at its disposal with Labour in Scotland at the cutting edge.