Leading article: Murder, manslaughter and our confused laws on killing

One way or another, it has been hard to avoid the unpleasant subject of murder this week, with the resolution of three unusually high-profile - and, in particular respects, controversial - cases. Damien Hanson, only 24 but with a string of serious convictions to his name, was convicted of murdering a wealthy banker during a robbery at his Chelsea home. A teenage girl and three young men were found guilty of manslaughter for killing a bar manager during a "happy slapping" spree in central London. And, in what is already turning out to be the most hotly debated verdict of the year, a jury accepted the manslaughter plea of an ex-soldier, Andrew Wragg, for the killing of his disabled son in preference to the prosecution's charge of murder.

Compared with the other cases, Hanson's seems simple. This was everyone's nightmare of a murder: a young man with a violent history turns up on the doorstep equipped to rob, and brutally kills the householder. The biggest controversy here is why Hanson was released so early from his previous sentence and why his probation appears to have been so inadequately supervised.

In the "happy slapping" case, the jury seems to have accepted the argument that the gang, while intent on random violence, had not set out to kill, even though they kicked a man to death. A senior Metropolitan Police officer spoke for many when he expressed disappointment that the jury had not convicted the gang of murder.

But it was the Wragg case that really ignited passions. While many sympathised with Mr Wragg's predicament as father of a severely disabled and terminally ill child, there was widespread consternation that his plea of manslaughter was accepted, even though the killing was clearly premeditated. We share that consternation. For while we did not, of course, hear the evidence first hand, the judgment seems to send a deeply disturbing message. This is that the lives of those who are too young, disabled or ill to speak for themselves are somehow worth less than the lives of others.

It is our view, and we are gratified to find it shared by so many, that the paramount duty of justice is to defend those without the power to defend themselves. In this respect, the court failed Jacob Wragg. And his father seems to have got off lightly. Convicted of manslaughter, he received a two-year suspended sentence on the grounds that nothing would be served by a prison term. Would it not have drummed the point home that killing an individual in these circumstances is as unacceptable to our society as killing someone older and fitter?

The controversy surrounding this verdict will continue to swirl. And so it should because, with the "happy-slapping" verdict, it highlights the current incoherence of our murder laws. Rather than being treated as a separate category, the category of manslaughter seems increasingly to be applied to premeditated killing where there are deemed to be mitigating circumstances or responsibility is judged to be diminished. Confusion has been compounded by recent legislation that stipulates mandatory sentences for a wide range of crimes, including murder. This has reduced the room for judges' discretion and may also deter jurors from delivering guilty verdicts.

The Lord Chancellor, Lord Falconer, said this week that the demarcation line between murder and manslaughter would be among the questions addressed during the Home Office review of murder laws that is in train. One solution being mooted is a US-style division of murder into degrees, although the Lord Chancellor says he is against this. We await the outcome with impatience. As this week's verdicts show, clarity in our murder laws is overdue.