Vandalism at bus shelters costs about �300,000 a year in the city

Staff at a control centre can shout through microphones to let offenders know they have been seen.

The stops are fitted with CCTV cameras that spin around on the sound of broken glass to capture vandals on video.

The aim of the innovative scheme is to reduce the amount of money spent on bus shelter repairs - currently running at about �300,000 a year in Birmingham alone.

Redvers Hocken, a security consultant involved in the project, said the technology was quite simple.

"It's an ordinary bus stop that's had sensors fitted to it.

The speaker is fitted on the roof of the bus shelters

"The other day, for instance, someone was bouncing a baseball against it and the sensors detected that and they were identified."

The bus stops are monitored in a CCTV control room that is linked to West Midlands Police.

Peter Adams, a spokesman for Centro, said a lot of money was being spent on repairs.

"On average it's �300 per shelter. We've got a 1,000 shelters. That's a �300,000 a year bill which we'd like to reduce if we can."

Peter Ryans, a spokesman for Birmingham City Council, said: "It's another addition to CCTV and in some places where we've already installed CCTV we've had an 80% reduction in crime."