Schools will be able to install metal detectors to scan pupils for knives under tough new security measures announced today.
Education secretary Alan Johnson said schools could introduce "arch" metal detectors, which students walk through, and "wand" detectors which are held close to the body.
The announcement comes just a week after ministers proposed new powers for teachers to search pupils for weapons without consent and carry out spot checks on youths at school, under amendments tabled to the violent crime reduction bill.
The measures come amid increasing concern about Britain's knife culture - a nationwide amnesty earlier this year resulted in 90,000 knives being handed in, and there have been a series of high-profile stabbings among young people.
Another provision in the violent crime reduction bill would increase the maximum sentence for carrying a blade or point in public from two to four years, and Mr Johnson said the combination of measures would act as a deterrent to young people.
"We're giving head teachers the extra powers they need to make their schools safe for all pupils and staff. If they feel it is appropriate they can now both screen and search pupils to prevent weapons coming through the school gates," he said.
"Parents will welcome the fact that we are sending out a clear message that bringing a knife into school is a criminal offence and will not be tolerated."
The new powers will be accompanied by additional advice to ensure schools stay within the law, and shadow home secretary David Davis urged the government to make sure this guidance was available soon to ensure schools knew where their responsibilities lie.
"It must take into account the issue of teacher safety and the extent of police involvement when searching pupils for knives," he said, adding: "What is important is that the government does not let this slip now they have made the announcement."
Liberal Democrat education spokeswoman Sarah Teather also warned ministers must also ensure children are properly taught about the dangers of knives and other weapons.
"Children often carry knives because they are afraid, and believe arming themselves is the only way to stay safe. We must tackle these underlying fears if we are to make our streets and schools safer," she said.
John Dunford, general secretary of the Association of School and College Leaders (ASCL), said today's announcement would send a "strong message" that schools would not tolerate violence.
Most schools would not have to use the new search powers, but he said: "Where there is a knife culture in the community, there is always a danger that this will spill over into the school itself and heads of these schools particularly will welcome the new measures."