Metal scanners cut Tube and rail robberies by half

British Transport Police statistics show there were 785 muggings on the Tube, overground trains and DLR last year compared with 1,433 such offences in 2006. Last year's total is also down sharply on 2005, when there were more than 1,500 robberies.

The fall follows a concerted drive to combat crime on the transport system using both scanners and plainclothes officers.

The effectiveness of scanners is highlighted in separate British Transport Police statistics that show 342 weapons have been seized nationwide since the force began using metal detection arches and handheld devices at stations.

The weapons, most of which were confiscated in London, include knives, machetes, sharpened screwdrivers, firearms and martial arts blades.

The seizures led to 329 arrests, including 159 specifically related to the possession of offensive weapons. The drive was launched in the wake of the Evening Standard's Safer Stations campaign, which called for action to protect commuters from crime.

It was backed by British Transport Police, who were given cash by the Mayor and railway companies to deploy more officers and the detectors.

The Standard's campaign came after the murder in January 2006 of young lawyer Tom ap Rhys Pryce as he left an unmanned Silverlink station at night.

Assistant Chief Constable Steve Thomas, head of British Transport Police in London, confirmed the fall in robberies was the result of two key factors.

The use of metal detectors at stations as part of Operation Shield had played a vital role in detecting and deterring criminals, while the increase in plainclothes officers tackling fare dodgers who were also often involved in crime had created a "degree of uncertainty for criminals".

"We are very pleased that robberies have fallen sharply and believe it is because the methods we are using are working," he said. "With scanners, we are finding that the more we use them, the less we are finding [weapons]. Fewer people are trying to carry weapons on to the transport system, which is one reason robberies are going down."

He added: "It is about making the Tube and railways harder places for the criminals to operate."

Today's figures will intensify the debate about the best way of combating knife and other violent crime in the capital, following the recent wave of fatal stabbings and shootings.

Ken Livingstone has expressed caution about calls for scanners to be permanently installed at stations, claiming it could lead to excessive delays during busy periods.

Tory candidate Boris Johnson is also less keen about permanent detectors, but has called for a big expansion of the use of mobile and hand-held scanners.

The use of metal detection arches and mobile scanners by British Transport Police began in February 2006 and has led to over 81,000 people being scanned and nearly 9,000 stopped and searched.