I don't think encouraging a person to do something that isn't a crime should be made a criminal act. It seems illogical.

And providing a person with the means to commit suicide can't really be made a crime either. If I give you a gun, I don't mean you to blow your brains out with it, and it isn't necessarily foreseeable that you would do that. Why should I be punished if you unexpectedly do turn it on yourself?

But if I give you the gun knowing or believing you will kill yourself with it, then I am assisting you, and that is culpable.

(Incidentally, there was an item on Radio 4 today about a woman with MS. She plans to go to Switzerland eventually, where assisted suicide is legal, and end her life there. She hopes her husband will be able to go with her, but she has asked the UK courts to clarify whether he will face imprisonment on his return: http://news.bbc.co.uk/1/hi/health/7644094.stm. However, this is deviating from the main topic under discussion.)