People should be entitled to use any force necessary to defend themselves against burglars, England's most senior police officer has said.
Recent crimes have put the self-defence issue under renewed focus
Met commissioner Sir John Stevens said householders should be presumed to have acted legally, even if a burglar dies, unless there is contrary evidence.
Laws which often seemed to favour criminals should be clarified, he said.
People should be prosecuted only when there was evidence of gratuitous violence, he told the Daily Telegraph.
Under the current law, people are entitled to use "reasonable force" to defend themselves and their homes.
It is up to judges and juries to decide what level of force is "reasonable".
Sir John said the public and police were confused about what that meant.
The law was currently sending the wrong message by encouraging burglars to break into houses in the belief that no householder could harm them, he said.
He told the paper: "My own view is that people should be allowed to use what force is necessary and they should be allowed to do so without any risk of prosecution.
"I'm not talking about guns but people being allowed to
defend themselves and use whatever is necessary to defend themselves against someone who may well be armed with a knife."
Sir John is due to leave the Met in January
He said the current legal test of "reasonable force" was too imprecise for people to consider in extreme circumstances.
Sir John was speaking five days after City financier John Monckton was stabbed to death by an intruder during an attempted robbery at his home in Chelsea, west London.
In October, school teacher Robert Symons was killed in his home in nearby Chiswick.
"Now is the time, specifically with these two cases we have had recently...for the law to be clarified," he said.
Responding to Sir John's comments, the Home Office said "no avenues have been
closed off" in its ongoing review of the laws covering murder.
But in April the government blocked a bill to allow householders to take unlimited action to defend their home, with Home Office Minister Fiona Mactaggart saying it would have created a "spiral of violence and retaliation".
Sir John said the case of Tony Martin, the Norfolk farmer jailed for shooting dead a burglar in 1999, had distorted the self-defence issue.
"[He] did shoot the burglar as he was running away. He did use a gun that was illegal.
Sir John's comments were welcomed by supporter of Mr Martin, Malcolm Starr, who recently encountered a burglar at his own home.
"Unless you face a situation like this you wouldn't know what you would do at the time," he said.
Current law 'works'
"I would have liked to have killed the burglar. The hatred for him being there, and attacking my wife was so great."
John Cooper, a leading criminal barrister and representative of the Bar Council, told the BBC the current law means "it is all down to 12 people on a jury deciding on the facts what is reasonable".
He said many lawyers shared his view that this works well.
A law change could lead to more confusion and cause problems, he said, such as whether a house guest who also attacks a burglar have the same "burden of proof" as the householder.
He said "month in month out," the Crown Prosecution Service dealt with cases where a burglar was injured but the case not brought to court.
Barrister and shadow attorney general Dominic Grieve, agreed with Sir John.
He said although householders who injure a burglar may not eventually be prosecuted they often faced "months of trauma" while a case was decided.
He said Tories were looking at legislation offering greater protection to householders.