This is a bit weird. I’m listening to classical music, sitting in the waiting room of Norwegian health centre in a smart district in central Oslo. There are tasteful pictures of female nudes on the walls and jars filled with condoms placed on every surface. It’s not where I would expect to meet a former Uefa referee.

Tom Henning Øvrebø spends most of his week here. The centre specialises in helping teenagers cope with pregnancy (hence the condoms) and Øvrebø, on whose door is written his name and ‘Psykolog’, is a trained clinical psychologist who rents his office from the Centre. Two afternoons every week, Øvrebø works with athletes at Norway’s Olympic training camp to improve their mental conditioning and it just so happens that on this particular afternoon, that’s where he is.

Øvrebø is currently recovering from a knee injury but is still an active referee in Norway. For some reason, I did not expect him to struggle with his time-keeping, but when he eventually arrives, he is full of apologies. He is wearing jeans, a pink T-shirt and Converse trainers — again, something of a surprise (though I knew he wouldn’t be wearing black shorts and a black T-shirt).

He is personable, charming and immensely proud of his refereeing career. In his office, there is a world map dotted with pins to indicate where he has taken charge of games. There are a lot of pins. He understands, though, that despite all the games in Norway, Uefa competitions and international football­ — he refereed two games at Euro 2008 and made the 14-man long-list, but not the final 10, for the 2010 World Cup — the one match he will be remembered for was the worst of his career. He laughs at how it works: for players, the memories are made from great moments, but for referees, from the mistakes. “That’s the way it goes,” he says. “I understand that and I don’t mind it at all. In fact, I learnt a lot from that game myself.”

Before we focus on the events of 6 May 2009, I want to ask Øvrebø about the psychology of the decision-making process under pressure. Between his two jobs, if he doesn’t have an idea about it I don’t know who will. 

As a psychologist trained to understand behaviours and motivations, did you feel at an advantage when you were on the pitch?

Sport is a lot of psychology, with emotions, conflicts and communication, so it’s not a disadvantage to have the theoretical background. You can understand the different psychological reactions of players and yourself but despite that, I still feel the same pressures and make the same mistakes as everyone else.

What came first, refereeing or psychology?

Refereeing! I started when I was 14 and my psychology studies began when I was 22 at university. I have been a referee for much longer. I played a lot of football and other sports when I was younger, and by coincidence I helped out as a referee and found it fun. From there it has gone step by step.

Why do you think northern Europe has produced so many elite referees in recent years?

Sweden has a good tradition of referees, so do Denmark and Norway, but it’s hard to tell why. I think we all like to work very hard, we have a professional attitude, like all referees from other small countries who are at a high level, we are always very well prepared off and on the pitch.

How would you describe your style as a referee?

I tried to get a good dialogue with the players. I would smile and be proactive, maybe I was a bit… not soft, as I had to be strict, but I tried to get good communication as it made it easier for me and for the players. The most important thing for a referee is to take the correct decision: if it’s a wrong decision, it’s still a wrong decision whatever your style.

In many ways, referees are like players: they make choices under pressure on the pitch and constantly have their performances assessed. Why is there not more support between the two groups?

They are not necessarily against us, but nor are they very supportive. In the heat of the game, when you think of all that’s involved — prestige, money, the high risks for the players —­ it’s not like their main thing is to support the referee. But the biggest difference between players and clubs and countries is all about how they behave towards the referee. You find differences in some countries, where it’s more okay to cheat the opponent and cheat the referee: for example, in England, they don’t like simulation but in other countries it’s more accepted.

If a player has a reputation as a diver, do you then take that into account if, say, he has been brought down in the box?

When you’re a referee at the top level, you have to be well-prepared and know how different teams and players behave. Some players may have the tendency to simulate more than others, and that’s a part of the referee’s preparation.

At what point does it become hard not to be prejudiced against a certain player?

That’s very important. Sometimes you have to take a decision in a split second, and you don’t think about which player is involved. At other times, if you know a player has a history of simulation and he has a situation in the penalty area, it can be that you have some of that history with you when you take that final decision. It could be that it sways you.

What about when players appeal for a decision: does that have any impact on you?

If I give a penalty, my attitude is you have to be 100% sure, not 50% or 60%. If it’s a free-kick in midfield, you could give it if it’s a ‘maybe, maybe not’. In the penalty area, you know that the consequences can be much bigger so I have to be 100% sure. It doesn’t help if players again and again try to appeal for penalty. The referee still has to be 100% sure. The assistants can help here: that co-operation is important and I have had incidents when they have given a signal if I haven’t seen it, or told me not to give one.

The difference between players and referees is that players are allowed to make mistakes, and referees aren’t. Why is that?

It’s hard to say but it’s certainly true that referees make mistakes like everyone else. It’s not just that the referee is the man in charge, the pilot, of the game but also important that he treats both teams equally. So if you make one mistake with Team A, you have not treated them equally. So what do you do with Team B? Is it correct to make a mistake with them too? Referees are not allowed to make mistakes and must treat everyone fairly. When I go out and referee, the players want to do their best but they make mistakes in every game: it could be a bad throw-in, free-kick, a foul or more serious, a penalty or sending-off. It’s part of football but hard for people to accept it when it’s a referee. If you’re a referee and you start to become afraid of making mistakes, then you’re in trouble. Your focus will be all wrong.

How would that affect your performance?

If you’re scared, you will think too much about the consequences and not have the courage to take difficult decisions. You may always try to play safe and that can be wrong sometimes: instead of taking the right decision, you maybe take the easiest decision. As a referee, that’s the wrong perspective to have.

How important is body language for a referee?

Very! Of course if I make a decision and it’s clearly wrong, then I will be in trouble but in my experience, it’s not the decision itself that gets you into trouble but the way you sell it, if you like. The way you sell it will to a large extent be influenced by your body language, your posture, your eye contact. Sometimes you can smile a little, but it’s not wise to stand there smiling if you’ve given a controversial penalty or as you show a red card. That would not go down well. You can use a smile when you give a decision to calm a player down or look away if you don’t want a player protesting against you. Using body language correctly is a big part of it. I remember when I was a new referee, there was a game at Brann Bergen, who have fanatical fans. It was on TV and I gave a penalty. But as I awarded it, I was biting my lip. There was a picture in the paper of it and my appearance makes me look unsure about the decision even though I wasn’t.

Body language, players protesting and making mistakes: it’s hard not to talk about your most famous game as a referee, the Champions League semi-final between Chelsea and Barcelona.

There’s a good picture of me from that game with [Michael] Ballack running after me appealing for a penalty. In that picture, it’s not very confident. I don’t look like the pilot of the game. When you look like that for every decision, it won’t be very easy to sell that decision.

I sensed that the more the Chelsea players appealed, the more it had the opposite effect and the more you wouldn’t give the decisions…

I can answer this not as a referee but as a psychologist: maybe the decision can go a bit in the other direction, to show, “I’m not influenced by the spectators.” If you say, “I shall not be influenced by the crowd, I will be extra strong,” it will still influence you one way or another. But it can be a negative influence for the team tying to appeal.

The Ballack appeal came after you turned down a fifth penalty appeal­ for handball against Gerard Piqué and it seemed the one most likely to be given. If that had happened in the first 20 minutes, before the atmosphere had become so hostile, would the decision have been different?

Unfortunately we will never know: I could have or I could not have! That’s the fascinating thing about refereeing. It’s all about the heat of the moment. In psychology, I can talk to my colleagues if there’s something I’m not sure about — maybe we should give this medicine or try this approach. But in football you need to take an instant decision in a split second. Sometimes that decision turns out to be wrong, but luckily most of the time the decision is correct.

We all know what happened after the game. Didier Drogba called the defeat “a fucking disgrace” and you were whisked out of the country in disguise and became the victim of threats from Chelsea fans. Did that affect your performances?

After the game, it’s hard because the media always remind you, call and contact you. Referees at international level are not allowed to speak to the media. We speak to the media [after league games] in Norway, after we have a shower, and I think the relationship between the media and referees is okay, we don’t have that much trouble here. In other countries, it’s harder to have that relationship. With international matches, you are not allowed to speak and in many ways it’s a positive, but it can also sometimes be a problem. The media can chase the story and not quieten it down immediately. Uefa says that if anyone did speak, there might be language problems with the quotes being mistranslated and with different football cultures, that could cause problems. So they decided to be strict. As a referee, I am loyal to that decision but sometimes it can be, well… To have a statement that says, “I’ve now seen the decision, I support my decision or unfortunately it turned out to be the wrong decision,” would be good. I’ve done that in Norway and the media and the supporters accept it. Maybe there will be some headlines on the Monday but on Tuesday the story is quiet. If you say nothing, the story carries on. If a star player missed an important penalty in a big tournament, it would be easier for him to release a statement the same day, instead of not speaking to the media, as that will continue to give focus on him and the story will last longer. It’s part of the job and I understand it, though. It’s like in psychology: I must conduct myself in silence. It would be interesting to speak about my clients, I have some fantastic stories to tell, but I can’t. Our employers don’t want us to.

Are referees better now than 30 years ago?

I hope so, but players have developed too. There is more emphasis on fitness and personality, on knowing the laws of the game more correctly; there are more courses, more fixed teams of referees and assistants now. Like the players, referees are better than 30 years ago, also when it comes to preparation, but do referees now make fewer mistakes? I don’t think so. The game has more speed, the players have more power, more money, are bigger stars, but if you look at the referees now and then, overall they are much more professional now.

Ben Lyttleton was speaking to Tom Henning Øvrebø for his book Twelve Yards: The Art and Psychology of the Perfect Penalty Kick to be published in spring 2014