At its appointed time, the moment of truth chose a plain basement hotel suite in Inverness on a grey afternoon to manifest itself. Afterwards, the man from the Guardian turned to me and we, unionists both, knew that the other had caught it too and that little required to be said: Scotland will become independent at some time in 2016 and there is nothing that the parties of the Union can do to resist it.

The messenger was Angus Robertson, the SNP MP for Moray, and also the most formidable campaign organiser of any political party in the United Kingdom. At a fringe event across the river and away from the main SNP conference, he had been debating the nature of the question that will appear on the party's prospectus for independence; should it be simply an outright "Yes" or "No" for sovereign independence or will a second question be added, the "devo max" option, which leaves Scotland independent of England in all but name?

Some of those journalists present may have scented the rare prospect of a schism opening up on this issue but in the end it didn't seem to matter. What did emerge was a statement of intent from Robertson showing that he and his colleagues have the battle plans drawn up, the intelligence gathered and the heavy artillery in place.

Yet this wasn't a barnstorming, blood-and-thunder peroration from the eloquent Robertson; instead, he sounded the death knell for the Union in elegant and mellifluous tones: "Independence is now not an abstract"; "The people want to be persuaded"; "This will transform people's lives". This wasn't a politician trying to sell an idea; this was a man telling us that the sale has been made and to start preparing for life in a different country.

Labour simply does not have politicians who can match the calibre of Robertson or any of Alex Salmond's ministerial team. Even if they did, they do not possess a vision and certainly not the purpose. Throughout the next few years, teams of SNP volunteers will call at every household in Scotland; they will be on a mission and be armed with a vivid narrative.

In response, Labour and the Conservatives have only talked of Armageddon. They tap the sides of their noses and repeat Sir Humphrey Appleby's nightmare "when the chips are down, the balloon goes up and the lights go out". They do not have a potent narrative for expressing their reasons for retaining the Union. While the SNP foot soldiers have already been out on manoeuvres, Labour and the Conservatives still do not know the identity of their next leaders. The SNP have fortified themselves with an array of technological wizardry that has already identified their core vote and probably where they all shop for their foundation garments.

The party now has almost five years to ensure that each of their most committed voters will turn out on referendum day. It has taken several years to harness this technology for the purpose. If Labour bought the gadgetry tomorrow they will yet be years behind the SNP in trying to unravel its secrets and unlock its potential.

To observe the annual SNP annual party conference is to witness an evangelical gathering in full cry. This isn't a political party and it's more than a movement – it's nothing less than a fully developed religion and its guiding star is now in the ascendant. Soon, it will settle above a place where everything for which it had ever hoped will come to fruition. It is reckoned that more than 1,000 party delegates have thronged the Eden Court theatre on the banks of the River Ness, an astonishing turnout that took even the gnarled veterans of the press by surprise.

Among the visitors and observers were delegations from around 20 or so overseas political parties and embassies. It seems they, too, have begun to notice that history-changing events are afoot and are eager to come, bearing gifts for the birth of a new order. Even the random nature of circumstances seems to be obeying a hidden but elemental force.

Events are now arranging themselves neatly in a line that suggests a preordained outcome. Alex Salmond, the first minister, was even handed a gift the day before his opening address to conference that must have caused him to entertain the notion that his destiny is intertwined with the nation's.

The Westminster government's cancellation on Wednesday of the £1bn carbon capture scheme at Longannet was handled in a high-handed and dismissive fashion by Chris Huhne, the energy secretary. It was an open goal and Salmond tucked it away confidently. Westminster again was "turning its back on the Scottish people," he said. The project had failed for want of a sum of money equal to one-tenth of the £13.4bn in oil revenues reaped by the Westminster government, he claimed.

For six months now, each of the two main opposition parties has been effectively leaderless as uninspired party contests have stretched on interminably. The Tory establishment's choice for the ticket is a young MSP who has never managed to win a constituency election, while Ed Miliband's knowledge of his party north of the border doesn't yet extend to knowing the names of all three leadership contenders.

By the time the referendum takes place, Scotland will have hosted the Ryder Cup at Gleneagles and the Commonwealth Games in Glasgow. The 700th anniversary of the battle of Bannockburn takes place in 2014. By the time of the referendum, Salmond is entitled to think that not only will we all vote for outright independence, but we'll all be wearing kilts and singing A Man's a Man for A' That in the old language as we do so.

My Labour roots are old and run deep, but on 20 October 2011 a small epiphany occurred on the banks of the restless River Ness.