Carrying a knife in 'hot spots' will mean prosecution says Brown

The Prime Minister said anyone carrying a blade in these areas will be prosecuted rather than given a caution.

Mr Brown also said he wanted computer game designers to stop their characters using knives and wants a total ban on the most lethal hunting knives.

His remarks come as Home Secretary Jacqui Smith prepared to bring forward a new Violent Crime Action Plan early next month and follow a spate of fatal stabbings, including three in London last month - Faridon Alizada, 18, and 16-year-old Nassirudeen Osawe around Christmas and Jack Large, 14, at the beginning of last month.

The Prime Minister, who said he was shocked to find almost 9,000 knifewielding thugs got off with cautions last year, insisted that the nation's 12 worst-hit areas - mainly London, Liverpool, Manchester, Birmingham and Nottingham - now operate a policy of zero-tolerance, prompted by Met Police chief Sir Ian Blair's decision last summer that officers should not give cautions to those found wielding a knife in London.

The Met and the Crown Prosecution Service said then that all offenders caught with a knife in the capital would be prosecuted and brought to court.

However, there is still concern that more than four out of five of those brought before the courts for carrying a blade escape a custodial sentence, despite a four-year maximum term.

Mr Brown said: "Society cannot cope with people carrying guns and knives and threatening to use them. There are boundaries you cannot cross - and one is this country's zero tolerance on knives."

Mr Brown also echoed David Cameron's call for the computer games industry to stamp out violence. "No one wants censorship or an interfering State. But the industry has some responsibility to society."

Mr Brown added that he wanted to outlaw sales of savage blades with no practical use for outdoor sports. "I want to look at other threatening knives - I will consider banning them."

Tories will wait to see if Mr Brown's words are matched by the actions of the Home Office. They say there have been several "summits" on knife crime but violent crime has continued to rise and unless the law is changed, ministers cannot interfere in the policing decisions of individual forces around the country.