THE Scottish Parliament has a poor record when it comes to criminalising behaviour. The Offensive Behaviour at Football Act is now the benchmark of bad law in Holyrood, along with the ill-thought-out and illiberal Named Persons scheme.

No one likes like sectarian behaviour or abusive people, but it’s very difficult actually to use the criminal law to prevent people being offensive and hateful to each other. But politicians like to be liked and they want to show they are “doing something” about it even when they don’t actually know what they are doing.

So alarm bells should have been ringing yesterday as the Scottish Government and the opposition parties, marched in lock step into the latest minefield of criminal behaviourism: outlawing psychological and emotional abuse in intimate relationships. When I heard Justice Minister Michael Matheson attempt to define such abuse the problem became very clear: he couldn’t.

Cutting people off from the outside world or forcing them to eat food off the floor – his main examples – are already illegal, as are stalking, harassment, threatening behaviour and intimidation. But this law is about something more nebulous. “Checking a partner’s access to social media” is apparently to become evidence of a crime punishable by five years in jail, as is “repeatedly putting them down and telling them they are worthless”. Better not tell drill sergeants or rugby coaches.

The groups advocating this law, and the police who will implement it, define psychological abuse as “coercive and controlling behaviour”. Well, I have known a lot of people who engage in coercive behaviour, and many of them are women. My mother was a wonderful woman in many ways but she was a very controlling personality. Passive aggression, or “gaslighting”, ‘is impossible to frame in law.

The Scottish Government papers on this repeatedly refer to such abusive “belittling and demeaning” behaviour only being criminal when it is “unreasonable”. But most people in relationships behave unreasonably, especially when they are under strain or when their relationship is breaking down. Unreasonable behaviour is legitimate grounds for divorce, but should not carry a prison sentence.

Everyone knows couples who seem to be in a state of constant low-level verbal violence, where they put each other down at dinner parties or in the pub. They get drunk and argue and say terrible things to each other – then the next day they are back to normal. Sometimes this kind of behaviour is almost a form of sexual foreplay. Trying to define how this is not psychological or emotional abuse is the problem with making such behaviour illegal. Policemen are poor relationship counsellors.

Family life is not for cissies. MSPs don’t read many novels and seem to have little knowledge of how rough people can be with each other. To start extending the criminal law into the subjective realm of intimate relationships is fraught with danger. Anyone who watched the BBC’s psychological drama The Replacement about psychological abuse in the workplace can see how difficult it is to make this a criminal offence.

And are teenagers going to be prosecuting parents for controlling behaviour when they’re grounded or deprived of electronic devices? Quite possibly, because they will be able to raise this with their Named Person, who will have a statutory obligation to intervene if it affects their well being.

I don’t want to make light of domestic abuse, which is a terrible crime. But unlike in soap operas like The Archers, emotional and psychological abuse is almost impossible to define, as the Scottish Law Society pointed out, except in the extreme cases which are already covered by the law. Intimate behaviour is by definition hard to monitor or corroborate. Similar English legislation on domestic psychological abuse has proved unworkable.

Passing legislation makes politicians feel good and pleases women’s groups. But I fear that there are going to be lots of cases of “he said-she said” coming before perplexed sheriffs who will, as with the Offensive Behaviour at Football Act, be reduced describing the law as “mince”.