There’s a loose cannon at every club and he will always fire. At each side I played for there was a training-ground incident. Nothing can prevent them, but when they are as serious as Joey Barton’s attack on Ousmane Dabo, it is right that the truth is made public and the FA takes firm action.

What sparks them off? Perhaps a player has been dropped, maybe he wants to leave, possibly the team is struggling, or he simply doesn’t get on with a team-mate. Or maybe he has personality problems, a flammable character. Managers always worry about the potential for fights. A Winston Bogarde, who is happy to sit in the reserves and take home his pay cheque, is rare. Players are desperate to play.

At Millwall we had a bust-up when the team were on a losing streak but the manager didn’t change the line-up. That annoyed the reserves, and when we had a first-team versus reserves training game, they took the opportunity to kick a few lumps out of us.

Whatever Barton’s motivation, it is right that he is held to account. There are times when you want the FA to be strong and it isn’t. There are times when cheaters, divers and foulers blatantly get away with it because the FA doesn’t step in. At least it is showing that it has got a spine on this occasion. Barton’s behaviour was too severe to ignore. The pictures of Dabo’s face are horrifying. No governing body should look the other way when someone commits a brutal crime on its watch.

The FA imposed bans on Eric Cantona, John Hartson and Ben Thatcher for their violent acts. What’s different here? That Barton has already gone through the courts for the assault doesn’t change the FA’s entitlement to punish him. He broke both the law of the land and the laws of the game. He deserves two punishments.

What he did to Dabo was on a football pitch, after all, even though it was in training. It was a while ago, but given the timing of his recent sentence for a separate assault, it’s an appropriate moment to ban him. Anyway: he was lucky to be in prison over the summer rather than entirely during the season. He deserves to miss a few games.

I’ve seen Barton on television in the past talking about how he’s a changed, calmer man — and that was before his imprisonment. Is he transformed now. Is he rehabilitated? Perhaps the FA’s sentence may help us to find out.

He must demonstrate that he has the strength of character to survive without football, to handle the frustration of training sessions with no proper matches.

To judge from his sad downward spiral since he retired, Paul Gascoigne couldn’t cope without the game. This ban is a small opportunity for Barton to show that he’s more mentally resilient than Gascoigne. Barton needs football, too — how else can he win back a shred of respect and credibility, except by performing his job with maturity and excellence? Working gives people purpose and focus. But he also needs to live without football. Being in jail is not the same as sitting in the stands watching his team-mates play. It’s a different sort of imprisonment and maybe it will do him good to face this challenge. But I’m not convinced.

I remember hearing a psychologist talk a couple of years ago, arguing that there was a scientific truth in the old saying “a leopard never changes his spots” — because from birth, key aspects of our behaviour are defined by genetics and we can’t modify the way our brains are wired. I’ve listened to plenty of troubled players over the years say they’re going to change. Maybe the gaps between incidents grow bigger, but beneath it all, their personalities don’t really alter. Hopefully, Barton will prove the theory wrong. He’s an outstanding footballer — maybe he can become an exceptional human being.