Knife thug caught on Boris walkabout

Mr Johnson was visiting Elephant and Castle to see how officers are using hi-tech scanners and stop-and-search laws to take weapons off the streets.

While he was there a youth leaving the Tube station walked through a scanner, revealing that he was carrying a knife.

Speaking just after the event yesterday afternoon Mr Johnson said: "If you look what has happened in the space of the last hour or so, the police have made two arrests and lifted at least one offensive weapon. If you talk to the community, who know the area, you will know how popular and effective these measures are."

Mr Johnson was watching Operation Blunt along with Home Secretary Jacqui Smith and Met Commissioner Sir Ian Blair.

Today he also announced plans for dedicated police teams which will patrol major bus interchanges and their immediate vicinity.

The "bus hub" teams will be made up of one sergeant, one police constable and seven PCSOs from the extra 440 uniformed staff previously pledged by the new Mayor. They will be supported by 1,600 special constables.

It comes after a week in which two young men in London were killed, leading to fears that violence in the capital is spiralling out of control. As part of measures to curb violent crime, police have been told they can stop and search people without reasonable suspicion.

In a further attempt to reassure the public, Mr Johnson has announced an extension of knife arches and handheld weapons scanners at Tube stations.

Mr Johnson said: "I believe this new crackdown by the police is a vital part of the fightback against the terrible scourge of knife crime. That's why I came to see the Met's new anti-crime operation at first hand with the Home Secretary Jacqui Smith and Met Commissioner Ian Blair.

"This is only one area in which we are making changes. I want more intelligence-led police initiatives focused on key estates, more hand-held scanners and knife arches to detect guns and knives and a huge drive to get kids off the streets into activities which raise their aspirations and help turn their lives around.

"Everybody is shocked by the level of violence we are seeing, particularly towards young people in London, and we must work as hard as we can together to reverse this dreadful trend."

Sir Ian denied criticisms that violence and youth killings were out of control and said parents had to play a role in combating knife crime.

He said: "I don't think it is out of control. This is a city of eight million people, but it's got to be kept in control.

"We cannot be in a position where murder after murder occurs with no apparent linkage.

"We have 150 of these arches now and we're going to start using them to make sure people realise they can't carry a knife.

"Our problem remains always that knives are in the knife drawer at home. If you want to reduce knife crime you have to start at home. As a parent you've got to ask your children what they are carrying."

The Mayor was unveiling the new "bus hub" initiative today at West Croydon bus station with Sir Ian and Transport Commissioner Peter Hendy.

The teams will police bus interchanges and the surrounding area, confronting crime and anti-social behaviour and reassuring the public.

The new teams will be deployed into a variety of interchanges, specifically targeting areas with greater problems.

They are intended to build on the success of the Safer Transport Teams and Safer Neighbourhood Teams.

Some officers will be put on the top deck of buses to support adults who want to challenge anti-social behaviour.

Mr Johnson said he wanted adults to stand up for other passengers when young people cause trouble.

The new Mayor believes the answer to tackling the recent murders was to first deal with minor crime.