What happened in George Square on Friday - the menacing, parade of Union Jacks, the flares, Nazi salutes and chants - seemed a universe away from the Edinburgh I left that morning.

No voters there restricted themselves to small smiles of relief.

In George Square in Glasgow the afternoon started tired and emotional. Yes campaigners, gathered to sing, hug, talk, encourage each other. Guitars strummed.

But the atmosphere changed as, towards the end of the afternoon, a cluster of Union Jacks started to grow, and there were rumours a thousand loyalists were coming.

I joked with Jake Kirkpatrick, a loyalist, that they needed more guitar music at their end of the square.

"We don't do guitars," he said, "only flutes." He added: "This city has got a great divide of sectarianism. What you were seeing with the Yes campaign was a bandwagon. They thought they could get this independence, rip up this Union Jack flag and cast us aside. It didn't work. They wanted to say there was something wrong with being proud and being British."

Loyalist banners began to be unfurled. A young man thrust a Union Jack at me, snarling: "You might want this for later." Then the square was a sea of red, white and blue.

"Bow to your British master," said one loyalist pointing to the ground before a Saltire-draped protester.

There were two lines, two factions, with a few metres and police separating them, and the bile rose in volume until it sounded like a distillation of football-stadium hate, with endless chants of "You can stick your independence up your a***'."

Christy, a Yes voter aged 16, said: "They're shouting and calling us scum because we're singing Flower Of Scotland ... It's just awful to come and have an opinion and feel threatened."

She and her friends said they were advised by the police to take their stickers off. Christy said: "They're not being told to take their Union Jacks down, so I'm not going to take off my sticker."

Many of the Yes campaigners were little more than kids of 14 who hadn't been able to vote, 16-year-olds who voted for the first time. The Union Jackers were older, almost exclusively male and white.

There was a huge rush as police tried to remove a trouble-maker. A wave of Union Jacks surged after him and police eventually appeared to let them go to rampage along St Vincent Street.

Thy were stokers of division, projecting their menace at the newly politically engaged young, propagating hate almost for its own sake.

Fortunately most people, and many of the young crowd, saw through that.