THERE are thousands of people required to make a Rangers versus Celtic match at Hampden memorable. In 2017, Herald Scotland spoke to just a few of the protagonists. We'll be reprising their words over the coming days in the build-up to Sunday's latest encounter which will all but confirm Celtic as champions should they win. First up is former referee Kenny Clark.

The match official: Former referee Kenny Clark
"Whenever an Old Firm match is coming up, you always think I would like my name to be in the frame for this one. But that is the heart ruling the head, because when your name actually comes out, you start thinking 'oh my God, why am I in the middle of all this'. I was always able to sleep the night before games, although I lost sleep after matches when things hadn't gone too well.

"It is an early start, which always adds a surreal element to it - it is never part of your normal routine to be up at 8am on a Sunday morning to be ready for the game. For Old Firm matches in Glasgow, you generally drive yourself to whatever hotel you are to meet up at. It was soup and sandwiches if it was a 3 o'clock kick off, but on this occasion what will be provided will be fresh fruit and cereal, that sort of thing, maybe a bit of toast. It will probably be a city centre hotel then they will be driven over in a people carrier to the stadium and straight into the underground car park.

The Herald:

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"From then, while I don't say there is a comfort zone as such, but there is familiarity to it, and Willie Collum is fortunately in that situation. He has done a number of Old Firm games and refereed at Hampden many times. I always took a comfort from looking at the team lines and thinking 'I have been involved in more Old Firm games than that guy, that guy or that guy'.

"It is not a case of marking cards, but we as referees would not be fulfilling our responsibilities if we didn't look ahead to games and think about the tactics which might be employed, both legitimate and illegitimate. Or where the flashpoints are likely to be. If I was looking at an Old Firm line up and I knew, for example, that Lorenzo Amoruso and Chris Sutton were going to be in direct contact with each other, then I knew I might have to alter my positioning slightly, be ten yards closer to them when the ball is played up.

“The same with Neil Lennon and Barry Ferguson or Alan Thompson or Fernando Ricksen. Referees have to be aware of that, or previous history between two players the last time around. You can't go into games like this other than with your eyes wide open. If you don't, you can be caught half a second short and that can make all the difference in an Old Firm game.

The Herald:

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"You dump the bags in the changing room, then go out on the pitch to acclimatise, make sure all the nets and markings are in order. There shouldn't be any issues at Hampden but you always have to check them just in case. You then check all the communications equipment, then an hour before kick off the match commander will come in to have a chat with you.

"For a cup tie it is always important to know what the arrangements are for penalty kicks, where they are going to be taken. Sometimes in the past I have had the two managers coming in, and they toss a coin, to decide what end the penalty kicks are going to be taken at. At Hampden at an Old Firm match it will almost certainly be at the toss of a coin in the presence of the match commander at 2pm.

"You go out and do the warm up, get stretched, and get used, a wee bit, to the crowd noise, then come back off, do the final preparations, get all the proper gear and equipment on, then check the boots. I always went into dressing rooms to do that but because Martin O'Neill gave people the cold shoulder treatment I know that Hugh Dallas and Stuart Dougal got fed up with it. They eventually wouldn't go into the dressing room but I am a bit thrawn about these things and I would still go in - because I knew he didn't want me to go in. And I wasn't going to let him decide what I do and what I didn't do. Going in and maybe talking to players is all part of establishing a rapport and I wasn't going to have that undermined simply because Martin O'Neill wanted to play mind games with us.

The Herald:

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“For a cup semi-final, particularly a live TV match, it is run to a tight schedule, so you make sure they are lined up in the tunnel at the right time and away we go.

"Refereeing, like everything else in sport, is a skill but you need a bit of luck at times and you do need a bit of co-operation from the players. The thing that makes life really difficult for the referee is when he has constantly having people challenging his authority, and squaring up to each other.

“You just hope they adopt the right attitude to things and you call the decisions right by being in the right place at the right time. Every referee is going out there hoping not to be noticed. You were always happy if you could come off and say, well 'at least we are not the headlines tomorrow'."