Harrison dropped only one round on each of two judges’ scorecards in his first defence of the WBO featherweight title he took from Argentina’s Juan Pablo Chacon in November.

And he came desperately close to handing the rock-hard Ulsterman the first stoppage defeat of his glittering career.

And Harrison will not be satisfied until he has achieved even greater conquests in the bigger matches which now lie ahead.

Harrison said: “I want the big fights for my fans. I’ll fight anybody in the featherweight division – I couldn’t care less who I fight.

“It’s something special to be named alongside men like Ken Buchanan and Jim Watt because they were my idols.

“But I’m only 25 and I’ve got a long way to go and a lot more titles to win.”

McCullough had endured 12 round wars against Naseem Hamed and Erik Morales but admitted neither had done as convincing a job as Harrison, who had his opponent on the brink of a stoppage in the sixth, eighth and 10 rounds.

Only McCullough’s legendary heart kept him upright and the Harrison camp had justification afterwards for insisting the challenger’s corner ought to have stepped in to stop the contest.

McCullough, who appeared at the post-fight press conference with an ice pack clutched to his swollen left ear, will take time to consider his future but the 32-year-old paid rich tribute to his opponent.

He said: “Scott is the strongest featherweight I’ve fought. Hamed and Morales were strong but this kid was unbelievable – he really shocked me.

“He is a lot stronger than the other two guys and I would fancy Scott against either of them. His was definitely the best job ever done on me.”

The cliff-hanger fight many expected was never likely to materialise as soon as Harrison took the centre of the ring from the opening bell.

He boxed with a terrific and focused maturity and made his weight advantage tell against an opponent whose greatest achievement came at bantamweight, where he won the WBC title eight years ago.

McCullough had since overcome a suspension caused by a brain scan irregularity and sparred over 130 rounds to make up for his recent professional inactivity.

But his punches lacked spark and Harrison’s relentless approach earned him 120-109, 119-109, 119-108 verdicts on the three ringside judges’ scorecards.

Had Harrison been punishing so convincingly anybody other than McCullough he would surely have earned the stoppage win he craved.

McCullough reeled across the ring under a Harrison assault in the sixth and despite responding with a right hook – his best shot of the contest – in round seven he endured more of the same in round eight, when referee John Coyle appeared poised to stop the contest.

Harrison’s father and trainer Peter admitted: “I signalled to the McCullough corner to stop the fight in the eighth because Scott was catching him with too many shots.

“If he’s losing every round and has no chance of winning the fight then why leave him in there – Kenny Croom (McCullough’s trainer) didn’t do his job tonight.”

Harrison could have sold out the raucous Braehead Arena twice over to Scots desperate for a long-overdue successor to their illustrious world champions of the past.

And his promoter Frank Warren insisted he would stay in Scotland for the second defence of his title around June.

The legendary former bantamweight champion Johnny Tapia was ringside to run the rule over his possible future rival but, having just returned from another near-death experience in America, June may come too soon for him.

Mexican Marco Antonio Barrera is the biggest fight out there but Warren’s plan to keep Harrison in Glasgow may work against that fight being made for the foreseeable future.

If it does not happen it will certainly not be through any reluctance on Harrison’s part.

Warren said: “All I hear from this fella is, I don’t want an easy fight, I only want to fight the best.

“I can’t think of a lot of fighters who have said that to me. A lot of fighters say it but Scott actually means it.

“If I said tomorrow it’s going to be Barrera, Scott would say ‘that’s great’.