The five-month long project to install cameras to record evidence that could be used in court has been funded by Northamptonshire County Council and rolled out to fire engines at stations in The Mounts, Daventry, Long Buckby, Moulton, Mereway, Kettering, Wellingborough and Rushden.

The new technology, which differs from that already used by crews in Corby, starts filming as soon as the fire engine is started and stops recording 30 minutes after the engine is stopped.

A spokesman for Northamptonshire County Council said: "We've taken the step of installing CCTV on county fire engines to act as a deterrent against attacks on firefighters as well as recording evidence which could be used in court.

"It's very sad that we have to go to such lengths to safeguard our firefighters, who are simply trying to carry out their job of saving lives and protecting the public.

"The CCTV cameras are there to protect firefighters and if they were turned off when the fire engine was in use, they would not be doing their job."

Fire crews in Northampton do not have access to the cameras and some members of the Fire Brigades Union (FBU) are concerned about the possibility of using the evidence against the firefighters.

Gary Mitchell, FBU secretary in Northamptonshire, said: "We've got them in Corby where they are operated by the officer in charge.

"We haven't seen the new brigade policy and we'll deal with it when we get that but our concerns are that they are being paid for for our safety and not to be used for any spying in the cab.

"We've had assurances that is not their intention. We've been asking for them for a period of time and we've had them for three to four years in Corby."

Earlier this month, firefighters dealing with a fire at a derelict school in Kingsthorpe were attacked by a gang of youths with stones and bricks.