It's bonanza time for Celtic and Rangers but both clubs have a dangerous problem with their next generation - Hugh Keevins

Ange Postecoglou and Giovanni van Bronckhorst should leave their diaries free for 2042. All of it.

If Martin O’Neill can fill the Armadillo in Glasgow tonight, 17 years after he managed Celtic for the last time, the market for day trips down memory lane is clearly alive and well.

You used to be only as good as your last game and O’Neill’s was a Scottish Cup Final win – but now you’re good for decades it would appear.

So Ange and Gio will still be box office on the 20th anniversary of one of them winning the league title for Celtic that nobody saw coming. And the other one taking Rangers to a European final at a time when it was thought that level of achievement was beyond the grasp of a Scottish club.

Nostalgia sells. Everything sells where Celtic and Rangers are concerned.

The commercial appetite for the pair of them is insatiable.

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The intensity of the rivalry between the two has become immeasurable.

Nir Bitton has been recounting racy tales of being unwilling to leave the house in the immediate aftermath of an Old Firm defeat in case he was ambushed at the shops.

Much to the amusement of his bemused countrymen now he’s safely back among them in Israel.

I met a Celtic fan last week who told me he’d gone