From the perspective of the club, it's ruthless pragmatism. Tierney, their best player, has expressed no desire to leave, and is a future captain and talisman. A key marketing asset in all commercial collaterals. He will improve and surely generate an even richer treasure in 2 years. He would be the rightful captain to capture 10-in-a-row.

So why consider this if you are Peter Lawwell? Celtic have realized and publicly confirmed that their annual participation in the group stages of the UCL (with its super-profit reward) is less probable with every year that passes. Celtic have also dropped the ball on the expected Dembele windfall, when he should have been sold in the transfer window after the Man City game. Regret generates anxiety.

Selling Tierney now for £30m should easily guarantee and maintain clear blue water between them and the best a Gerrard-aspired Rangers could achieve. It’s a trade that locks in 10-in-row, in a moment when UEFA monies may longer hit the Balance Sheet. And after all, they have a decent young replacement in Calvin Miller. Ruthless pragmatism? You decide.

From the perspective of the player, or better, the human, he is torn. He is deeply “Celtic minded” but also an elite athlete, susceptible to whisperings in the ear of a song called Ambition.

The lad has recently changed agent, to a boutique very focused on the practical matters in life. Coincidence? He now, they will say, has the chance to secure his family’s financial future. No doubt there would be a promise of a golden hello incentive to his family. And enough money for three generations down the line.

It will also be suggested to him that he can’t wait for the 10th record title. At best, one more year at Celtic, before he is undeniably treading water. Another treble doesn’t advance his legacy, the SPFL doesn’t push his progression, and getting skelped for 5 or 6 in the Champions League doesn’t look good for a defender.

And what if you get an injury, Kieran? Those soft seductive tunes played by top agents are a winning argument for any young man. Throw in the classic, “you’ll come back one day“, and it’s overwhelming. He leaves, albeit reluctantly. And rightly so. Whether Everton, Spurs or Man United is another argument, not for today.

From the perspective of the manager, it’s a blow. But he’d be a hypocrite if he used his best Irish silver tongue to push back. He himself likely tosses and turns each night on the horns of the same dilemma. Legacy and timing. Can he still win the treble without Tierney? Most certainly yes, and Miller is an excellent prospect.

Will his chances in the UCL group stage be significantly downgraded by the loss of his star left back? Of course they will. But does going from a 20% to a 15% chance really represent a paradigm shift? It’s not at the margins. He will come to peace with the loss soon enough and reflect on investing that cash in quality central defenders and a goalie. And he will not be far behind the boy.

From the perspective of the fans it is a tragedy. There are 5 stages of grief: denial, anger, bargaining, depression, and acceptance. Those brave hacks currently opining the whole saga are already subjected to the denial and anger part. “He is Celtic. He won’t leave”.

The bargaining phase will begin soon with the bragging rights about how good the fee was, and how it cements the Celtic dominance. That in Glasgow is called whittabootery. The more interesting phases are depression and acceptance. It raises more questions than answers. Will fans of a huge club like Celtic accept the reality that all, yes everyone, with international class, MUST leave?

Will they accept their club actively marketing “Celtic minded” local idols for the wedge? Will they join the dots and see that there is thus a de facto quality ceiling on a Celtic player; where any exception appearing, like Kieran Tierney, is doomed to be fleeting? Will the younger fans, not already having experienced the pain of Dalglish and Nicholas, accept this?

That last question is the key one. The modern Gen Z fan is in no way as bought-in to local fare as we were. His (and increasingly her) choices are now infinite in the world of Twitch, with mega-star players projected to global celeb status. Will the club loyalty hold? Will the Christmas Celtic pajamas guarantee a lifetime season ticket customer? Will Dad’s tears at Walk On still resonate?

Or.

Will a moody, ballsy teenager turn to the old man and say “Dad, I’m not watching this anymore. It’s mediocre at best. Any talent we discover is off as soon as.....by definition, we are watching players who can’t get into a big league”?

And what does Dad say?

Now, undoubtedly the Celtic brand loyalty is infinitely stronger than almost any club. And whether the bloggers like to or not, much, if not all of that, is due to a to-the-death rivalry with Rangers. Yes, if you know the history you see that we were borne as a reaction to them, and are still defined by our desire to dominate them. They are NOT the peopel!!!!

So whilst that rivalry/hatred continues, and any drop in player quality is evenly balanced, interest in the club, Glasgow Celtic, should persist.

But do not make the mistake of thinking that the departure of Tierney can be intellectualised like Van Dijk. And that the impact will be manageable as easily.

This transfer will be an epiphany moment for many, especially those under 25.

For me, remembering Charlie, my heart goes out to the kids.