Legal view: Floodgates won't open - evidence of disorder will be needed

I've come across this symptom before. I've defended cases where people have suffered sleep disorders.

There was one where a man tried to strangle his wife during their sleep, another where someone walked out into the street and struck someone.

There are an assortment of different sleep disorders which are only now being recognised by the courts.

In this case the expert evidence was led by the defence and another position led by the Crown, and it has been accepted that this is the proper syndrome by the jury.

The judge will have told them that, if they accept that, he must be acquitted as he did not have the intent to commit the crime.

If sex takes place when a woman is asleep then, under our law, it is rape. But if it is happening where the man is also asleep and acting subconsciously, most reasonable people would then accept that it should not be rape.

If anyone thinks this will open the floodgates for this defence to be used falsely, I can tell them now that won't work.

Anyone who wants to rely on this defence will need to be backed by experts, and there are a number of different ways of telling if they are genuine.

In the same way as psychologists do, experts apply tests to see if you suffer from a sleep disorder, and if you do it will not be restricted to an isolated incident where a crime is committed.

There are tests that get to the core of this disorder, so your word will not be good enough.

Equally, if you are drunk, that would not work as a defence. The court would have to accept that a genuine disorder has been established in evidence and the accused had no intent to commit the crime.

It is not unlike an epileptic who has an unexpected attack while driving and mows someone down in the street.

Now if I'm an epileptic and banned from driving because of it, then I would be entirely responsible if I caused an accident. But if it was my first epileptic fit then the courts would accept that I am not responsible for my actions.

In the same way if he knew he suffered from this condition, and knew that because of it things happened at night that should not happen, that would have been difficult for his defence.

So if he came back before the courts for a similar crime and used the same defence, serious questions would be asked.

• Paul McBride is one of Scotland's leading QCs.