Jude Bellingham shows Rangers the transfer intangibles they need to stop Celtic and Oscar Cortes is the start - Kenny Miller

I can never forget the memory of an 18-year-old kid playing for Borussia Dortmund at Ibrox and trying to prevent Rangers from reaching the last 16 of the Europa League.

He was an English boy making big waves in a foreign country and I marvelled at the way he was making demands of German internationals during the game. And in their native language. His name was Jude Bellingham and I don’t need to remind anyone of where his career went from that night in front of a full house in Glasgow.

I’m not for one minute suggesting Rangers should go out and break the bank to sign the next Jude Bellingham, but I am saying that the club’s due diligence on any transfer target has to take into account the player’s mental strength and ability to handle a city where judgement can be passed on you in a month, never mind a season.

That’s why I’m delighted to see Oscar Cortes back at Rangers from Lens in a deal which means the club is obliged to buy him for £4.5million next summer. Obviously there is a risk element attached to a deal constructed in that fashion, but my belief is that Cortes can handle what’s ahead of him at Ibrox.

I know it was only a small sample size of seven appearances and one goal before injury struck during his first loan spell at the club last season, but I saw enough to convince me he can be a real asset to Rangers.

He had the work ethic, the balance and the hunger to get into goal scoring positions. Oscar was Ryan Kent, but with a greater threat about him. Rangers have been screaming out for a player in that position and Oscar has the full package.

My due diligence is done when a player puts on a Rangers jersey and has to be a hit. It’s not just about performances. There has to be, like Bellingham in that European