I have an example, but I'll put it at the end so that we can get the Breivik discussion out of the way first.

In American TV-land (and possibly in the real USA – I don't know), prosecutors are obsessed with getting the most convictions and the longest sentences possible, so that they can get re-elected for being "tough on crime". Whether they get the wrong guy, or someone who had a good excuse for what they did, doesn't seem to be a concern.

In sensible places, the prosecution tries to get it right. This means that, if a person is nuts, you don't pretend they're sane so you can have them locked away in a prison, where their condition will get worse, instead of a mental hospital, where it will get better.

The maximum 21-year sentence is another good reason for it. I should point out that, if at the end of the 21 years, a prisoner is judged to still be a danger to the community, they can be kept inside. But you can't judge that now; you have to judge it at the end of the 21 years (in 2033).


Breivik wants to be declared sane and acquitted on a defence of necessity. I'm sure his lawyer has told him that's a stupid idea, but it's not the lawyer's decision to make. Breivik has his reasons, and from his point of view they seem to be good ones. If he's declared insane, his political point is discredited. (There's more detail on this in the other replies to this thread, so I won't repeat too much.)

Also, he has said he'd rather suffer a death penalty than go to a mental institution. Indeed, he says he didn't expect to get off the island alive anyway, so he didn't really have a plan for afterwards.

Now, the example, which is a Scottish case:

Ross v HM Advocate 1991 JC 210

Robert Ross was in a bar drinking beer from a can. Someone put drugs (temazepam and LSD) in the can without his knowledge. As a result he went on a drug-fuelled rampage and stabbed several people he didn't know with a knife. At his trial for attempted murder, he didn't enter an insanity plea because at the time, the law said that anyone acquitted by reason of insanity had to be detained in a secure mental facility – the court had no choice. Since basically all the facts were agreed, the judge said there was no ground for an acquittal, and the jury convicted him. On appeal, the prosecution said the conviction had to stand, because the only possible ground of acquittal was insanity, which hadn't been pled. Thankfully the Appeal Court saw sense and quashed the conviction. If you need help understanding why, look up the term mens rea. This case is now the foundation for the defence of automatism in Scots Law.