David Blunkett, the home secretary, believes existing legislation is tilted too far in the criminals’ favour.

The Tories are to give full backing to a private member’s bill from Patrick Mercer, the MP for Newark, which offers complete freedom from prosecution to homeowners who take any action against an intruder so long as it is not “grossly disproportionate”.

Mercer, one of whose constituents was shot and killed by Tony Martin, the Norfolk farmer jailed for five years, said last night: “I wish to rebalance the law in favour of the victim rather than the aggressor.”

But he added that Martin, who shot a fleeing 16-year-old burglar with an illegally held gun, would not be protected by his law.

The rethink comes as Sir John Stevens, the Metropolitan police commissioner, said that people who defend their families and property should face prosecution only in “extreme circumstances”.

Stevens said homeowners should be presumed to have acted legally, even if a burglar dies, unless there is contrary evidence.

He added that the current law which sanctioned householders to use only “reasonable force” should be clarified to favour the homeowner rather than the criminal.

The Home Office said yesterday that the issues raised by recent cases of homeowners being murdered by intruders or using weapons to defend themselves would form part of the review of murder and manslaughter law being carried out by the department.

A spokesman said: “The home secretary thinks it is right for the review to address complex issues such as provocation, partial defences and self-defence as it relates to murder and manslaughter.”

Last week John Monckton, a financier, was stabbed to death trying to defend his family from intruders at their home in Chelsea, London.

Explore UK News

• Crime News

• Education News

• Health News

• Science News

• Scotland News

Times Recommends

• Revealed: how Eurocrat leaked secrets over dinners
• Politicians use the net to brainstorm
• British spy in longbow plot to kill Himmler