Liverpool defender Andy Robertson accused assistant referee Constantine Hatzidakis of elbowing him in his side’s 2–2 draw with Arsenal; the altercation took place after the half-time whistle; former Premier League referee Dermot Gallagher analyzes the incident

Liverpool’s 2-2 draw with Arsenal was marred by a half-time incident involving home defender Andy Robertson and assistant referee Constantine Hatzidakis.

It was alleged that Robertson was nudged by the linesman at the half-time whistle. The Liverpool left-back approached the official and footage appeared to show his elbow hitting the defender.

Robertson received a yellow card from referee Paul Tierney for his role in the incident, while Liverpool captain Jordan Henderson approached officials to discuss what happened.

Professional Game Match Officials Limited (PGMOL), which governs referees in English football, said it was investigating the incident, as was the Football Association.

Former Premier League referee Dermot Gallagher takes part in a Q&A below on the next steps:

Do you think Constantine Hatzidakis nudged Andy Robertson?

We don’t know what happened. We start from what we see and assume.

Only he can answer that. We can only speculate and I hate to do so because of the ramifications it may have for Constantine Hatzidakis, Andy Robertson and football in general.

You look at different angles, you have to be careful not to start speculating and end up thinking and getting inside his head, wondering why this and that happened? You have to go through the facts and see what happens.

What are the next steps now that the PGMOL and the FA are investigating the situation?

Interestingly, the PGMOL said they were going to come out and look at it. They will talk to the parties involved. They will be able to talk to Constantine Hatzidakis very quickly since he is one of their members. I would be amazed if they didn’t try to talk to him after the game, as soon as he showered and changed! Time is running out, people need to know what happened. When we go deeper into that, that’s the next step in the process.

I think, without a doubt, the PGMOL and Howard Webb will talk to Hatzidakis, determine his views, his thoughts and how he feels. The FA have already announced they will speak to him and Andy Robertson on Sunday and Monday. It’s just a matter of following the process.

Could Paul Tierney have done something more in this situation?

It is difficult for the referee. For example, if a player comes up to me and says “I’ve been spat on” – I think that’s the most unpleasant thing – but there’s not much I can do about it unless I have it seen or that one of my officials has seen. I can’t be satisfied with what a player tells me. I have to educate people. The players sensitized Paul Tierney. But we don’t know what really happened during this time.

You know and have worked with Constantine Hatzidakis. How is he as a referee and a person?

He really is a great guy. I’m not just saying that. I remember him when he started refereeing. He was very young, passionate and wanted to learn.

I remember when he came to a game at Millwall training ground and ran the line for me in a reserve game, and after the game he was thirsty for knowledge and asked what had happened passed in the game.

He worked his way up to become a National League referee. I had the privilege of watching him and he is a good referee. You don’t reach this level without being a very good referee.

He had the opportunity because of the course to become a referee or assistant, he chose assistant. And he went from there to become an international assistant. He’s at the top of his game – and he’s a really nice guy.

Can a referee simply crack under heavy pressure or in front of a large crowd?

I can only speak for myself. I refereed in really hostile atmospheres and in really difficult matches. I refereed a South American Champions League final in Brazil – it’s a tough environment.

But I could never imagine myself in a position where I could lose my temper. When you referee, you have to be in control. This is the only way to control players.

So I would be amazed if he was in that position. I’m not saying he didn’t, but that’s foreign to how we’re brought up as referees.

Is this incident common in football?

I have never seen an incident like this on any level. I have had the misfortune to hear of some of my colleagues who have been involved in unsavory incidents.

But it’s so unusual. It’s just a matter of being careful that we don’t start speculating and making up your own mind about what happened.

Some say Hatzidakis should be dropped for next weekend? is this the right thing to do?

It depends on the result. Undoubtedly, the PGMOL and the FA will want to act quickly. But there is no point in acting quickly and coming to the wrong conclusion.

They must have enough time to talk to all parties, collect all the evidence and gather the witnesses. Then put that together and come to the conclusion. Then you can make a decision.