Greater protection from prosecution will be offered to "have-a-go heroes" under plans to strengthen the law on self-defence to be announced today.
Jack Straw, the Justice Secretary, will promise that people who fight back against intruders or challenge robbers in the street that they can act without fear of ending up in court.
His move will coincide with a pledge from Jacqui Smith, the Home Secretary, that the Government will show "zero tolerance" to all forms of crime and anti-social behaviour.
Mr Straw, who has taken the law into his own hands four times to tackle muggers or burglars, will acknowledge public fears that the criminal justice system can be tilted in favour of offenders. He will tell the Labour Party conference: "I know from personal experience that you have all of a millisecond to make the judgement about whether to intervene.
"In such a situation, the law on self-defence works much better than most people think, but not as well as it could or should. The justice system must not only work on the side of people who do the right thing as good citizens, but also be seen to work on their side."
Mr Straw will make clear that law-abiding citizens will only be able to take proportionate action to defend themselves or their property or to catch a criminal. He will stress: "There is a critical line between responsibility and recklessness."
With the Conservatives scoring relatively strongly on law and order, Mr Straws and Ms Smith will go on the attack to demonstrate Labour's crime-fighting credentials. Following the recent spate of gun deaths, the Home Secretary will make a fresh pledge to get tough on armed crime, but also acknowledge the need to help young people trying to break free of the influence of gangs.
She will announce that six more sexual assault referral centres, where rape victims can receive counselling and advice on dealing with the police, are to be set up. Ms Smith will promise police will be provided with the latest technology, including hand-held computers, to enable them to spend more time on the street and will commit the Government to boosting neighbourhood policing.Reuse content