FORMER Scottish referee Calum Murray today looked back on the explosive Old Firm “shame game” he took charge of in 2011 and admitted “it was my toughest”.

Murray hung up his whistle at the end of last season after spending no fewer than 15 years as an SFA Category One official and five years on the FIFA list.

The 48-year-old, who is now a referees’ mentor and observer, was involved in many massive matches in Scotland and further afield in Europe during his time as a man-in-the-middle.

But the infamous Scottish Cup fifth round replay between Celtic and Rangers at Parkhead four years ago was the most memorable – for all the wrong reasons.

At the end of 90 explosive minutes there had been 34 arrests inside the stadium, 13 yellow cards, three orderings off, several touchline altercations and a bust-up in the tunnel.

The fallout from a game Celtic won 1-0 was unprecedented; First Minister Alex Salmond branded the scenes as “shameful” and called a government summit.

That resulted in a contentious piece of legislation being passed which continues to cause widespread consternation to this day.

Murray said: “It was a tough game, probably my toughest game in many ways. There was a really high crime count that night, the highest crime count of any game I was ever involved with.

“In five Edinburgh derbies I refereed I had no red cards. In six Old Firm derbies I had nine red cards. That tells its own story.

“All of the misconduct was in the last 15 minutes of both halves. The first half hour in both halves were actually fine. They were competitive, but they were typical Old Firm games. There were a crazy 15 minutes in both halves.

“There were a number of factors which came into it. Rangers and Celtic had played each other an awful lot that season.

“Celtic had won their previous encounter fairly comfortably and Rangers hadn’t competed very well. All the ingredients were there. The characters on the pitch contributed to it as well.

“Occasionally you do get games like that. Two or three will go by which are competitive. Then, all of a sudden, you get a wee spike in one of them and that makes it a particularly difficult game for a referee.”

Murray was physically manhandled by Rangers centre half Madjid Bougherra as he attempted to show him a second yellow card in the final minute of the match.

And the Gers temperamental on-loan striker El Hadji Diouf suffered the same fate after the final whistle for dissent.

Murray said: “Bougherra subsequently apologised, both publicly in the media and to me personally. He said sorry the next time he saw me at a game. It was a case of turn the page and move on. It was a spur of the moment thing, passion.”

The fourth official possibly endured an even more torrid evening than Murray - Iain Brines had to step in and separate the opposing dugouts as tempers flared after Rangers midfielder Steven Whittaker got sent off.

Brines was then forced to intervene as Celtic boss Neil Lennon squared up to Rangers assistant Ally McCoist after words were exchanged at the end of the game.

“Poor Iain!” said Murray. “Seriously, though, he was a big policeman. He could look after himself.

“They (Lennon and McCoist) are two guys I have got a lot of respect for. They were the Old Firm managers when I was coming through. But that night Iain called me over and I tried to get them to calm down.

“For a while, that game followed me around. People would see me and whisper: ‘See him? He was the referee in that Old Firm game’. They are exciting matches. They can be great spectacles for fans. But for referees they are challenging.

“I have to be honest, I really enjoyed them. But the baggage which comes with them can be quite difficult to deal with. It is something I don’t feel you can ever fully prepare yourself for until you go through it.”

Murray also refereed the Scottish Cup final between Celtic and Motherwell at the end of that season –and enraged both sets of fans with his decisions on what was another difficult afternoon.

Those cheering on Motherwell felt that Celtic stopper Daniel Majstorovic should have been ordered off for first a foul on their striker John Sutton and then a hand ball.

Those backing Celtic were convinced Motherwell defender Stephen Craigan deserved to be red carded for deliberately handling the ball on the edge of his penalty box.

Murray said: “The first half was probably one of the toughest 45 minutes of football I have ever had. The conditions were horrendous. The pitch was in great condition, but it had been raining since about five o’clock that morning. The place was treacherous. It was a nightmare.

“I had to make allowances for that. There were a couple of robust challenges which I tried to manage. If you watch it back you might think I was a bit lenient, but, overall, I was quite satisfied. There were maybe one or two incidents I could have handled better.

“I got quite a lot of criticism, but the players were fine with me after the game. I think they realised what had happened. Ultimately, it was quite a good experience, I quite enjoyed it.”