THE ambience was somewhere between the AGM of a slick public relations firm and a fairly staid after-show party.

In a boardroom and suite at the rear of a Glasgow hotel and just a car park away from BBC Scotland’s headquarters, the Remain campaign’s command and control operation north of the Border united old foes from the "other referendum" with the sharp-suited young party apparatchiks ubiquitous on election nights.

Former special adviser to Alex Salmond, Kevin Pringle, Scottish Labour kingpin Frank Roy and John Edward, the former head of the European Parliament office in Scotland, huddled around laptops, phones glued to ears as feedback flowed in from colleagues in the field.

In the adjoining green room, broadcasters from France and just across the road at Pacific Quay hunkered down for the long night ahead.

“One of two things is likely to happen here tonight”, said one of the leading lights of Scotland Stronger in Europe.

“Either the Scottish vote will carry Remain across the line for the whole of the UK or we’re going to have a situation where Scotland votes right across the board to stay in the EU but is taken out against its wishes by the rest of the UK.”

Astute stuff.

As the first results came through there were sharp intakes of breath through teeth. Newcastle was maybe too close for comfort but Sunderland was a unique case and not a bell weather. Or so they hoped.

Also, some of the Scottish results were double-edged: areas like the Shetland and Western Isles, amongst the most likely Scots Leavers, voted to Remain. But other areas expected to deliver handsomely were disappointing. A turnout of 56 per cent in Glasgow was poor.

“It was always entirely possible it could go either one of two ways but it's too early to make predictions”, said Mr Edward, Stronger In Europe’s Scottish spokesman.

It was a while before a slew of Leave results was countered in any way and the tension, tangible from the very start of the night, was temporarily lifted.

Exeter and Oxford were followed by London’s Lambeth in declaring for Remain. For only the second time that night the pro-EU vote had inched ahead. Next up was Glasgow, which, low turnout aside, voted overwhelmingly for Remain. It seemed the pendulum had swung and Scotland was the engine room driving the Eurosceptics out.

“We’ve still got the big cities to come,” said one buoyant Remain team member. “Manchester nor Edinburgh or the London boroughs haven’t declared yet. The vast majority of England’s population has yet to come out.”

The signs were auspicious. But they barely lasted minutes.

By the time Scotland’s sole Labour MP, Ian Murray, and Scottish Government minister Humza Yousaf, who was heading the SNP Remain campaign, arrived from interviews at BBC and STV the Scotland map was almost entirely yellow yet the mood had moved from cagey to flat.

“From a Scottish perspective we’re delighted and it's looking likely all could declare for Remain,” said Mr Yousaf at around 3am.”But I’m deeply concerned at the wider picture. We need to protect Scotland’s interests and that means nothing’s off the table.”

In one last moment of light relief an overseas journalist asked whether anyone within the Remain team had a grasp of working French. None had. The irony wasn’t lost.

Patrick Bourke had worked for the Irish Labour party until a few months back and had thrown his effort into the Remain campaign in recent weeks.

The 28-year-old from Limerick had some very tangible concerns. “I’m not saying Ireland will return to The Troubles but this will be the location of the UK’s only land border with Europe. One one hand we’re told this will have no impact yet Leave repeatedly talk of tightening borders.

“Which is it? The Peace Process has worked because the border is largely invisible. I fear what the repercussions will be if check points go back up.”

Stephen Dewar, also 28 and from Glasgow, said: “This is going to be chaos. There’s no plan here. I’m genuinely shocked how this is unfolding.

“I lived in Hampshire for a while and even then just couldn’t have anticipated this.

“Just look at that map. That’s a cultural border we have and not just a political one.”

Jerome Jadot is a journalist with French public service radio station France Info. “This is thrilling and exciting” he said. “It’s not how we do elections in France.

“In France the story will be the UK leaving. But there is an awareness of Scotland more and more. You seem to know more about the Auld Alliance but there’s a recognition we both have our difficulties with England.”

As the declaration was made shortly after 4.30am the entire operation fell silent. A failed round of applause was followed by sombre back patting, a few hugs and eventually tears. All had known electoral defeat in the last couple of years but none with the consequences of what unfolded over just five hours.

“When the final result was given that was basically the signal for us to pack up the campaign and go home”, said Mr Edward. “But when the numbers came through you thought ‘what the hell has happened’. No-one knows what this means.

“How will these people (who voted Leave) feel when what they’ve been promised isn’t delivered? They’ll feel lied to again.”