London's 8,000 buses are equipped with CCTV cameras. A team of 70 analysts watch hours of footage to pinpoint alleged crimes.

OPERATION BusTag - the Met Police team dedicated to tackling criminal damage on buses - made 80 arrests in April.

In February, the BusTag team won a Met Police award for innovative policing.

The success of the operation is in part down to a good working relationship with London's 23 bus operating companies and their teams of CCTV analysts.

At First's Orpington depot in Faraday Way, St Mary Cray, CCTV analyst for the south east Michael Rogers is celebrating a good month.

During the last visit to the depot by Bromley's Safer Transport Team, PCSOs were shown 17 incidents and positively identified eight of the suspects.

Mr Rogers said: "The good thing about youngsters is they tend to repeat, so once they are on the system, they are easier to identify.

"The PSCOs know these kids because they are going into schools."

The 44-year-old father-of-three, from Green Street Green, added: "When First offered me the job in August last year, they said they wanted someone with local knowledge.

"I travel into and out of work on the bus, so I think News Shopper's Shop A Yob is fantastic.

"The more it irritates them, the better. When we make an arrest, it is fantastic."

To get a conviction from CCTV footage, the analyst needs to put together a data pack to send to BusTag officers in London Victoria.

The pack includes a report on the incident either from the driver involved or from the bus company's management.

There will also be an estimated cost of the damage and a report from the analyst which includes CCTV images.

Because of data protection laws, the analyst is the only person authorised to look at the CCTV footage.

From the date, location and time of the incident, the analyst can find the relevant footage as long as it is reported within a seven-day period.

Mr Rogers said: "If the incident is reported between seven and 14 days after it happened, the chances of finding the relevant footage fall to 75 per cent."

This is because footage is automatically recorded over in a loop if it is not saved.

To ensure the footage will stand up as evidence in court, it needs to show the suspect committing a crime.

Failing this, footage needs to show the bus before and after damage was caused and include a recognisable shot of the suspect.

Mr Rogers said: "In Orpington, we are known for the quality of our evidence rather than the quantity."

Once the BusTag officers receive the packs, they can try to identify the suspects and make arrests.

The information gathered by analysts looking through thousands of hours of footage is also vital in directing police operations.

Their data is compiled into reports which show how many and what kind of incidents are happening, as well as where and when.

Safer transport teams can see where the crime hotspots are and target these areas.

Mr Rogers said: "We are working under the radar of the travelling public who are not aware of the machinery involved.

"We are pro-active in dealing with the problem, but it is not always obvious."

HOW THE SYSTEM WORKS

THERE are eight cameras on a single-decker bus and 17 on a double-decker.

They record footage at 25 frames per second onto a hard drive which stores seven days' data.

Mr Rogers is confident as technology advances, the quality of CCTV evidence will improve and the analysts will get better at identifying criminals.

The latest CCTV system currently being trialled by bus companies downloads the footage via a wireless internet connection when the bus returns to the depot in the evening.

When an incident is reported, a request is made by the analysts and a computer downloads the relevant footage from the hard drive.