Peter Ross at large: Riding high in Hawick

• Horsemen, led by Acting Father Grahame Nichol. Picture: Jane Barlow

THE bells of St Mary's are striking six as the Drum and Fife Band marches into the hopeful morning light, playing the Hawick anthem Teribus, martial beats echoing in empty streets, raising rooks from gables. It is the duty of the band to waken Hawick and to alert its folk, known as Teries, that today is the Common Riding, the loudest, proudest day in the town's calendar.

In truth, everyone knows already. Hawick is decorated in the Common Riding colours of azure and gold: flags strung across streets and hung from balconies; shop windows tricked out with ribbons; pansies in planters blooming in the approved livery. Even the climate has obliged with a honey sun in a pale blue sky.

The Common Riding takes place each year on the first Friday after the first Monday in June. Dating back to 1514, it represents both the capture in battle of an English flag by the youth of Hawick and the ancient custom of marking the boundaries of the common land. There are similar festivals throughout the summer in the Borders towns and elsewhere, each a spectacle of pageantry and a booze-up, but Hawick is first and so has a particular air of abandonment and joy.

"It will never be forgotten in this toon," says Ronnie Nichol, a giant of a man, steam rising from his bald head as he removes his band cap. "Things are changing all over the country, financially and in every other way. But this will always go on."

At this, his friend and bandmate Ian Anderson nods with great certainty. But what makes them so sure their tradition will endure? "Because fathers sing Teribus to their sons instead of lullabies," says Anderson.

Nichol has been in the band for 37 years, Anderson for 33. That's the way things go in Hawick. You find a role and stick at it. Yet there is no sense of dry obligation. Rather, these men and many other Teries take enormous pleasure in participating in the ritual.

"Whatever high point you have in Glasgow it can't touch this," Anderson explains to me, a Glaswegian, with gentle pity. "If you're a Celtic fan and they won the European Cup six times in a row then that might come close. But it wouldn't be the same."

There are ceremonies within the ceremony. On the Kirkstile, at the foot of the church, a large group has gathered. Some wear tweeds and golden waistcoats. Others wear bowler hats and carry riding crops. Some have beer on their breath and whisky on their mind. A wee girl in pyjamas waves down from a window. It is quarter past six in the morning.

In the midst of the crowd stands Mike Aitken, a 50-year-old joiner in his 11th year as Song Singer. It is he who leads the songs throughout the day. For the moment, he must perform his other task – distributing snuff from an old ram's horn to those brave enough to fight for it. A cry goes up – "Let's have it, boys!" – and suddenly Aitken is at the centre of a writhing, struggling, grunting scrum, all hoarse curses and builder's bum. Men fall to the ground, heads smacking stone. Someone loses a shoe.

Occasionally, a burly figure emerges, grinning broadly, their fingers dark with snuff dug from the horn.

Afterwards, Aitken has blood on his neck and battered brogues. "That was pretty coorse the day," he grins. "That's as rough as it's been.

"The word on the street last night was a bunch of Denholm boys were coming up to pinch the horn. There was 50 quid to whoever got it from us. They did their best but the horn's still oors."

The tradition, after the Snuffin', is to retire to the pubs for the day's official beverage – rum and milk. "Have a wee taste," offers Graham Bennett, 44, standing outside the Exchange Bar. "It's not bad after you've had a couple." Bennett is visiting from Musselburgh. "I was Honest Lad in 1986." The places that hold Common Ridings send envoys to each of the others. Often these men introduce themselves as Coldstream or Kelso and so on, rather than giving their names. Where they're from is, today, more important than who they are.

Inside the Exchange, it's rammed and they're singing Up Wi' Auld Hawick. A group of friends, old mill girls, are swaying with their arms linked, bellowing it out. "Where are you from? Scotland On Sunday? We'll still be singing come Sunday," says Helen Ford, 69. "This means everything to us. I can't explain it to you. It's in your blood."

Ford has a glass of rum and milk in front of her, but her pal Merle Campbell is on the gin and soda. It's only seven in the morning. Too early yet for rum, she reckons. Her fingernails are painted blue and yellow.

Only one year did she miss the Common Riding. She was in Germany and listened on that day to a tape of the old songs. "Oh the tears were streaming down my cheeks. It was heart-rending."

At 8.25am, we get our first glimpse of the Cornet, the young man chosen to lead the riders as they travel on horseback around the boundaries of the common land. He also carries the flag, representing that captured from the English all those centuries ago. It is a tremendous honour. You are the toast of the town; Mr Darcy for the day.

This year's Cornet is Michael Davidson, 25, who works in forestry. This is the most important day of his life. He first rode out when he was seven years old on a pony called Rupert. Today, he sings the Old Common-Riding Song outside the town hall, reading the words from inside the top hat which he holds in front of him, then it's on to his horse, Storm, and away through the streets.

Some 329 horses are taking part this year. Each horse and rider is cheered by a crowd of several hundred as they canter out from a vennel. The band are at the front with oak leaves on the brims of their hats; then comes the Cornet in his green tail-coat and white breeks. The visiting dignitaries from other towns are also on horseback. The four men from Jedburgh, splendid in their Balmoral bonnets are particular favourites with onlookers. One dashing fellow wears a burgundy sash which identifies him as The Linton Whipman.

At the sight of the Cornet and riders, none cheers louder than Charles Whillans, known as Chuck or Mr Common Riding, a small jovial man in a blazer. At 87, he is the oldest living former Cornet, having discharged that duty in 1948. He hopes, he says, to have his coffin draped in the blue and gold flag; though, of course, his many friends in Hawick pray that day is far off. It was Helen Ford who pointed him out to me. Whillans is the first Cornet she remembers; he visited her school in his green tailcoat when she was five. Now both are old but seem young. "Here's my Common Riding kiss," she says, pecking his cheek. "Thanks bonnie lass," he replies.

One important stop on the journey of the riders is The Hut, an old barn at St Leonards farm, a short distance outside town, with Rally Roond Oor Cornet written above the door. This event, at which songs are sung and toasts given, is arguably the emotional highpoint of the day. It is men-only. The proceedings are piped out by tannoy to the assembled womenfolk picnicking on the grass.

The principal ladies, among them 23-year-old receptionist Kirsteen Hill, the Cornet's Lass, sit in their finery on benches beneath the branches of an ancient oak, having travelled here by stretch limo. "I'm right proud for Michael and happy that he's got to fulfil a lifetime dream," says Hill. She doesn't seem bothered at having to remain out here, wrapped in her official Cornet's Lass blanket, while her boyfriend is warm indoors.

She might even be better off. The Hut is a hot, crowded, beery place with red-faced, damp-eyed men crammed together, elbow to elbow, jowl by jowl, banging on the tables and singing lustily. They alternate spoonfuls of curds and cream – known as "soor dook" – with more rum and milk. One young man stumbles out and embraces his mother. "Don't go back in just yet," she tells him. "The longer you stay out here, the less drink you'll have."

Eventually, proceedings at The Hut are over and the riders make for the Moor Racecourse, where most of the townsfolk have set up a makeshift camp of gazebos strung with gold and azure bunting. It is Agincourt meets T in the Park. The revelry will go on until dawn. "This is the best party in Scotland," says one woman, and she may have a point.

The Common Riding is certainly vastly more enjoyable than, say, Edinburgh's Hogmanay, perhaps because it is in no way geared towards tourists or the media. It is by the Teries for the Teries. Though the locals are very welcoming, the Common Riding would happen if no-one from outside town was here. Indeed, its very insularity is the key part of its identity; it is about boundaries, about the community that holds you in its sweet embrace. It is not narrow parochialism, it is big-hearted local pride.

Steph Reith, a local woman here with her husband and teenage children, sums it up. "A day out of Hawick," she laughs, "is a day wasted."