Sir Robin praised Eastlea Community School in Canning Town who took part in a trial, with the Metropolitan Police, using walk through metal detector arches to scan pupils as they entered the school.

It was the first time these have been used at a Newham school. Parents were sent letters informing them of the scheme.

Sir Robin said: "It is important that both young people and staff feel safe at school. These detectors act as a deterrent, give out a zero-tolerance message and help reassure young people and their parents that we in Newham take safety seriously.

"The vast majority of young people do not carry knives, but there is a tiny minority who think it is acceptable to do so. They seem to think it keeps them safe when in fact the weapon could be used against them. These arches are not about treating our young people as potential criminals; they are about prevention and safety."

Officers from Newham police's Safer Schools Team carried out the searches using the detector arches and wands.

Newham Police Borough Commander Det Chief Supt Nick Bracken said: "While there is not a problem with knives at Eastlea or other local schools, we know that some young people feel the need to carry them.

"We hope the arches will work as a deterrent to ensure the safety of all those who attend school. Our aim is to reduce fear in young people and help them develop a respect for their peers and the wider community. We thank Eastlea for their help and commitment to making the school safe and secure."

The Mayor added: "The detectors are a quick, reliable and non-obtrusive way of detection without making young people feel like they are being victimised. Together with the police we want to build a culture of safety - pupils should not feel the need to protect themselves.

"We want them to know that if you carry a knife in Newham you run the risk of getting caught, going before a court and getting a custodial sentence. Parents also need to make their children aware of the dangers and risks of carrying a bladed weapon.

"Random checks will catch offenders unawares. I want schools to be safe and secure places to learn. I would encourage others to considering using their powers to screen and search because it reassures young people and could help avoid future tragedies."

Eastlea School agreed to take part in the trial following an appeal by police during school assemblies. Comments from the pupils have all been positive.