The signing that set Celtic back years and brought about a trophy 'abyss'

It was the transfer that stunned Scottish and world football as Rangers openly signed a high-profile Catholic for the first time.

Mo Johnston wasn't just any Catholic.

The self-confessed and die-hard Celtic supporter striker had been paraded by then boss Billy McNeill at Parkhead on the eve of the 1989 Scottish Cup final as Johnston spoke of an emotional homecoming.

Celtic would go on to defeat Rangers in the 1989 Scottish Cup final with a solitary goal from Joe Miller to prevent a Light Blues treble.

The ecstasy would turn to agony days later as Rangers manager Graeme Souness persuaded the striker to join his Ibrox overhaul.

Celtic failed to win a single trophy between 1989 and 1995 and Grant admits it took the club years to recover from losing out on Johnston in such a brutal way.

Grant said: "Mo Johnston was a terrific player for Celtic and nobody could ever hide that fact.

"I would never say anything detrimental about him because as a teammate he was different class.

"He did what he did.

"I met him many years later when Celtic was over in Canada and it was the first time I remember meeting him and he was trying to explain but it was going in one ear and out of the other.

"It was great to see him and he was a cracking player for Celtic, I cannot take that away from him.

"Every single game he played for Celtic he worked his socks off and he was a great striker and a great finisher. It was just disappointing the way it ended.

"I sat beside Mo on the team bus on the way to Hampden Park for the 1989 Scottish Cup final and he had posed for the famous pictures the night before.

"Mo told me on that journey that it was just a case of sorting out a couple of details before he signed the contract. I thought nothing of that at the time.

"People talk about Rangers' nine-in-a-row achievement but the day Celtic lost Mo to was a big, big part of that.

"Even though Celtic were not as good or had players of the same quality of Rangers in our side at the time we knew if we had Mo in our team we would have been fighting for championships and winning cups.

"We failed to take some opportunities because he was not part of Celtic's strikeforce."

Grant was drafted into the Scotland squad set up after the 1989 Scottish Cup final and he made his debut against England and won his only other cap against Chile in the Rous Cup competition.

However, it was Johnston and Ally McCoist who broke the bombshell news the striker had performed a U-turn and was going to sign for bitter rivals Rangers.

Grant said: "I was with the Scotland squad for the Rous Cup and we were training down in Ayrshire. I was sitting with Mo and Coisty on the bus going to training. It was Coisty who told me that Mo was signing for Rangers.

"I thought he was joking and pulling my leg and I told him it was wishful thinking and I was laughing away as I thought it was a total wind-up. Sure enough it was true and Mo was signing for Rangers.

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"I couldn't believe it. It was a massive, massive blow to Celtic.

"If you are going to lose Mo Johnston, then that's fine, you can lose him to another team - you just can't lose him to Rangers.

"If Mo had signed for another club then we would have all accepted that and moved on.

"It's a massive reason why Rangers went on to clinch nine-in-a-row.

"Rangers got stronger and at that particular time were spending money and buying the best players and if you do that then there is every chance you will be successful.

"That's what happened and he scored in his first game at Ibrox against Celtic.

"If Mo had signed for Celtic we would have challenged no doubt about that.

"I have always felt that six-year abyss would not have lasted as long as it did as it took Celtic a while to recover from it."

Both players fates would be intertwined again during a derby clash in 1991.

Grant was booked for hacking Johnston, receiving a second yellow card and was dismissed by referee Andrew Waddell seconds later for charging down the subsequent free-kick.

It was a match that has since been dubbed the St Patrick's Day Massacre.

Four players - Grant of Celtic and Terry Hurlock, Mark Walters and Mark Hateley of Rangers all saw red as the Hoops triumphed 2-0 at Parkhead in a Scottish Cup quarter-final clash.

It was Grant's only red card in the derby fixture and arguably one of his biggest regrets in his career to this day.

Grant said: "It is one of my biggest regrets.

"Who did I bring down? Mo Johnston!

"The referee has blown the whistle and awarded the free-kick and he's booked me.

"I am aware of that as I am not stupid but I have started three or four yards behind the wall as I am the charger and new rules had been brought in about doing that kind of thing.

"I should have let someone else be the charger and swapped with somebody in the wall.

"I have started my run from behind Mo and I have charged the ball down really quickly.

"New rules applied, I have been hit with a second booking and I've been sent off.

"How do you explain that you once got sent off in a derby against Rangers for charging the ball down at a free-kick!

"The funny thing about it is I remember sitting in the dressing room and we were 2-0 up and I thought I was going to get dogs abuse if we blew it.

"I heard three more sets of studded footsteps and I was wondering what had happened and there were huge cheers and roars coming from the Celtic supporters.

"I thought we were 5-0 or 6-0 up and I didn't realise that the three Rangers boys had also been ordered off.

"Everybody who talks to me about the Rangers sending off asks who did I boot or punch?

"I had three sendings off in my career and every one of them was for a second bookable offence.

"For the sort of player, I was supposed to be that's not a bad disciplinary record.

"The sending off against Rangers is a big regret. It still galls me to this day."