Fewer murders will lead to a mandatory life sentence under radical proposals published today.
The Government's law advisers suggested creating a new framework of "first degree" and "second degree" murder alongside a revised definition of manslaughter.
There should also be new categories of homicide for specific offences, such as assisting suicide and infanticide, the Law Commission said in provisional proposals.
Crucially, killers who intend to cause their victims "serious harm" but not to kill will be treated as second degree murderers and will no longer face mandatory life sentences.
"The foundation on which our proposed framework rests is that the most serious offence within the framework, and the only one that should attract the mandatory life sentence, should be confined to cases where the offender intended to kill," said today's document.
The second tier would include killings through "reckless indifference" to causing death, intention to do serious harm and cases where the killers claim they were provoked, suffering diminished responsibility or under duress.
The Law Commissioner Dr Jeremy Horder said: "The law is not what the public thinks it is.
"It is confusing and unfair, and the judiciary have to adapt it to meet the needs of the 21st century on a case-by-case basis.
"In undertaking this review, we have not ruled anything out."
He described the proposals as a "ladder of offences", which reflect different degrees of culpability.
The proposals have already been harshly criticised by victims' groups because they open the door to an end to mandatory life sentences for murderers.
The Law Commission's report is the first stage in the most radical review of murder laws in England and Wales for 50 years.
The options will be up for discussion before the commission presents a final set of recommendations to the Home Office next autumn.
The report recognised that there would be two main objections to limiting first degree murder to intentional killings.
Some would argue that it should include cases where a killer realised it was "highly probable" that his or her actions would lead to a death, it said.
But the commissioners concluded that first degree murder "should not include cases where there was merely a risk of it happening".
It added: "Taking a risk, even a high risk, of killing someone is recklessness and is very serious but it is not the same as the deliberate taking of life."
Objectors may also argue that it will be difficult to prove there was an intention to kill. The commissioners said that they rejected this argument.
They also proposed that first degree murder should not be confined to premeditated cases.
The report said of the proposed category of second degree murder: "We think that the second tier should cover cases where the defendant intended to cause serious harm, which in fact results in death.
"We think that the third tier should cover cases where the defendant intended to cause some, but not serious harm, which in fact results in death."
Last August, the Law Commission condemned the law on murder as "a mess" and said a major overhaul was required.
Currently, everyone convicted of murder has to receive a life sentence but the judge recommends a minimum term - or tariff - each offender should serve.
Those convicted of "mercy killings" receive far lower tariffs than, for example, those who have killed a random stranger.Reuse content