The head of the Crown Prosecution Service has called for British murder laws to be replaced with an American-style system grading the seriousness of the killing.

Ken Macdonald, the director of public prosecutions, believes the change would help prevent killers being acquitted due to the current legislation's inflexibility. "I am strongly in favour of a system that recognises degrees of homicide," he tells the Times today. "There should be degrees of homicide, not just murder or manslaughter, but three or four degrees." Mr Macdonald added, though: "If we are talking about a serious homicide, killing with an intention to kill, that should attract a mandatory life sentence."