Murder life sentences questioned in attitudes research
Research into the sentencing of murderers has found no evidence that people support mandatory life imprisonment.
The study found that those questioned had varying views about how long to jail murderers.
The report, funded by the charity the Nuffield Foundation, said the public had limited understanding of how convicted murderers were sentenced.
Researchers interviewed more than 1,000 people across in England and Wales.
The mandatory life sentence for all murders was introduced in 1965, when the death penalty was abolished.
The study by Coventry University's Professor Barry Mitchell and Oxford University's Professor Julian Roberts found the vast majority of those interviewed incorrectly believed there were more murders in England and Wales now than a decade ago.
But they went on: "We found no evidence of overwhelming or widespread public support for automatically sending all convicted murderers to life imprisonment.
"We found considerable evidence that the public perceive significant variations in the seriousness of different murder scenarios."
Public support for the life sentence increased in relation to the seriousness of the crime, said the paper.
It also asked people what they thought about "joint enterprise" murders - typically gang killings where more than one member was present, but only one of them carried out the attack.
The study said that just one-fifth of those surveyed said it was right to convict someone of murder if they had not struck the fatal blow.
The authors said that their survey also indicated the public only vaguely understood that murderers released on a life licence could be recalled to prison at any time, despite having served a minimum term, known as a tariff.
"We found evidence that in relation to the more serious murders, those members of the public who favour release at some stage are content for sentencing judges to be given some measure of discretion, but would like that discretion to be limited or controlled, either through legal guidelines or through minimum and maximum periods of imprisonment," said the report.
The research team said that if the law mirrored public opinion, then the mandatory life sentence would be reserved for the most serious murder cases - and judges would be able to sentence other murderers to different terms.
The Law Commission, which advises government, proposed such a three-tiered system in 2006 - but the then government rejected it.
It suggested first-degree murder, carrying a mandatory life sentence; second-degree murder, with a life term at the discretion of the judge plus sentence guidelines; and manslaughter, also with a maximum penalty of life.
Despite the lack of political support for such a move, top lawyers - including Keir Starmer, the current Director of Public Prosecutions, and his immediate predecessor Lord MacDonald - have continued to argue for the introduction of distinct first and second-degree murder charges.