There are few moments in life when you truly revel in your roots. A couple of weeks ago, I dragged myself along to Shepherd's Bush Empire to watch The Proclaimers play London for the first time in several years. This was no time to haver as a diminutive Scottish geezer ran up to a microphone before relaying the news to an exuberant crowd in a distinctive Lothian patois: "Ladies and gentlemen...the boys are back in town.."
Craig and Charlie Reid, or The Proclaimers as the twin brothers are better known, had the joint bouncing with a riveting new song Whatever You've Got before trotting out their cascading songbook including 500 miles, Letter from America and Sunshine on Leith. It was a memorable night, the sort of evening that reminds you of The Proclaimers' unique brilliance in writing a soothing catalogue of working class, comical, memorable and socially piercing songs.
It was a similar sensation last night at Celtic Park when the Bhoys were back in town. Like The Proclaimers, Celtic on song truly are something to behold, but do not take my word for it.
"The Celtic fans are very special and the club and players can be very proud of them," said the waspish Barcelona and Spain midfielder Andres Iniesta on Tuesday, obviously aware of what was about to hit him. "They are the best I have ever heard and I am sure playing in front of a crowd like that can make a big difference for the players."
When the team and fans come together, as it did last night, Celtic can be an irresistible force in the world game as Barcelona, arguably the greatest side assembled in the history of club football, discovered, much to their sodden disbelief in Glasgow. Forget being the 12th man, Celtic fans were the 13th, 14th and 15th man.
Celtic Park on a European night crackles with a raw energy and emotion that is utterly unique in world football. There is a togetherness and passion in the vast arena, rebuilt by former owner Fergus McCann some 17 years ago to house 60,000 supporters on evenings like this, that seems to energise the team to scale heights that obey no laws of sporting logic.
It a curious theatre that somehow installs belief into the home players when they come bounding up the tunnel before The Celtic Song is trotted out by Glen Daly.
It is perhaps not well publicised, but the Real Madrid coach Jose Mourinho recalls the exhausting 2003 UEFA Cup final in Seville, won 3-2 by his Porto team after extra-time, as his most memorable match in football because of the atmosphere Celtic supporters created in the Andalusian city.
There was a gorgeous, heady atmosphere of safety, song and siestas in Seville that week despite over 100,000 fans, 80,000 or so following Celtic, adorning the heart of the old town. I remember sitting having a bite to eat in the centre of Seville with a few Porto fans, who seemed to be as impressed by the good nature of the visiting hordes as Mourinho. Celtic were rewarded with trinkets from UEFA and FIFA for the conduct of their fans. The vast majority of their support continues to travel well, but the true hue of their colour continues to be best projected at Parkhead.
Celtic have a redoubtable record at Celtic Park in the Champions League in recent times usurping Juventus, AC Milan and Manchester United. But this Barcelona side represents the ultimate form of big game when you dust down the old blunderbuss.
Celtic seem to wallow in upsetting sides who they would have no right to share a park with if football was played on a balance sheet. As the club's manager Neil Lennon rightly pointed out last night, Barcelona wheeled on substitutes David Villa and Cesc Fabregas, signed for almost £60 million, to rescue the match; Celtic turned to 18-year-old Tony Watt, a £50,000 signing from Airdrie from the danker regions of the Scottish game. Watt scored a wonderful goal to finally bury Barca. And all of this a day after the club's 125th birthday.
Celtic's 2-1 win over Inter Milan in the 1967 European Cup final remains their most poignant time, but this was hardly the poor relation.
To suggest Celtic played anti-football because they could not get hold of the ball, as several papers have suggested, is utterly immature. Celtic played with a controlled aggression throughout the night, and there was a directness and purpose to their play that Barcelona seemed to lack as they invariably ran up cul-de-sacs when their short passes on the edge of the home box came up short.
Once clubs like Celtic are on a financially level playing field to Barca, then we can deal in the aesthetics of how the game should be played.
Celtic would be realistic contenders to win the English Premier League within five years if they were allowed access to the millions of pounds of television money in which substantially smaller clubs revel in across the border. The sheer size of the club would demand it. Nothing will ever deter this onlooker from that belief.
In a week which saw Barack Obama with his Kenyan roots re-elected as US president, perhaps it was no surprise Kenya's Victor Wanyama, 21, was the driving force in the inundated midfield area for Celtic. Like Obama, Wanyama should be thinking about four more years.
Wanyama could develop himself into a finer player before heading for a larger and richer league. Wherever he goes in Europe, he will not play before a more appreciative group of fans. Why did Henrik Larsson opt to spend seven years at Celtic when clubs such as Manchester United coveted him?
The Scottish Premier League receives a bad press simply because it is a small impoverished league in Northern Europe that lacks media finance, but it cannot be so bad even after the liquidation of Rangers and the predictions of Armageddon that followed their demise. Real Madrid are the only other club to have wounded Barcelona in such a manner this season.
There remains a general ignorance towards the goings on in Scotland. One bloke from a London national tabloid could be heard referring to Celtic's ground on a national radio station this morning as Ibrox. Astonishing, but true.
Singer Rod Stewart knew the significance of the night. He could be found with tears tumbling from his eyes at the full-time whistle, but a man is nothing without his football club.
"Celtic is important to me in as much as it's one of the only constants in my life over the years," commented the comedian Billy Connolly. "I have changed and become various things but it is the one constant. Religion, friendships have come and gone, likes and dislikes have come and gone, but Celtic has remained."
An old mate of mine continues to complain that The Proclaimers' Sunshine on Leith should have been a Celtic song. That tune belongs to Edinburgh's Hibernian just like passing football belongs to Barcelona. But Celtic have their own special assets, namely a ground and a group of fans that money cannot buy. It may not be Leith, but there is plenty of sunshine to be found in Glasgow's East End on such manic nights of glorious drizzle.