The most senior judge in England and Wales has backed moves which could end mandatory life sentences for murder.
Lord Woolf backs the Home Office review of murder sentencing
Lord Woolf has said he opposes Parliament passing laws that force judges to impose particular sentences.
He has supported the Home Office's decision to launch a review of the law on murder, saying: "I'm not in favour of mandatory sentences full stop."
Currently all people convicted of murder must receive a life sentence but judges recommend a minimum term.
People convicted of "mercy killings" tend to receive far lower recommended terms - or "tariffs" - than, for example, those who have killed a random stranger.
Last October, the Home Office announced a major review of the law on murder - the first for more than 50 years.
Lord Woolf's comments follow concerns expressed by some judges that they were being straitjacketed by ministers over how to punish offenders.
Asked if he favoured ending the mandatory life sentence for murder, he said: "I think there is a need for a review.
"I'm not in favour of mandatory sentences, full stop.
"It may not make any practical difference if you have the right definition for murder.
"If you intend to kill someone deliberately then a life sentence may be the only appropriate sentence."
The Times newspaper reports that a consultation paper is expected by the end of the year, with a final report by the end of 2006.
Degrees of severity
It says Prime Minister Tony Blair will outline plans for a new definition of murder to exclude crimes such as mercy killings, or create a new category of murder with different sentences to reflect degrees of severity, within weeks.
Regarding his support for the Home Office review, Lord Woolf added: "You can have someone who has a relative who is suffering pain of severity which someone in my position can only try to imagine, and they feel it's what that person wants - to be relieved of that misery.
"To treat that person as you treat someone who deliberately kills for a different purpose is very difficult.
"That is why we look to have a punishment that fits the crime."
Last August the independent Law Commission, which advises ministers on changes to the law, said that legislation governing murder was "a mess".
Its research revealed that 64 respondents out of 146 - including 21 judges - believed a mandatory life sentence for every case of murder was "indefensible and should cease".
Last month Ken Macdonald QC, the Director of Public Prosecutions, backed the introduction of a system that recognised degrees of homicide.
The Criminal Justice Act 2003, which applies to offences committed from 4 April this year, requires courts to impose mandatory sentences on any of 155 offences under certain circumstances.