The push to install CCTV cameras in taxis intensified when Keighley cabbie Mahmood Ahmed was murdered by a passenger in Oakworth in April last year.

Many taxi companies across the district stepped up efforts to facilitate the installation of potentially life-saving CCTV systems in their vehicle fleets.

But the cost of effective CCTV systems - quoted in some cases as more than £1,000 per vehicle - has preyed heavily on the minds of company bosses drawing up business plans.

Such financial pressures led taxi firms to demand a change in the rules to allow taxis across the district to break with tradition and display advertising for the first time.

Bradford Council is in the process of considering the request for advertising on cabs - a measure designed to ease the burden of installing CCTV.

Metro Keighley Taxis is among the companies hoping revenue from selling advertising space can cover the lion's share of the estimated £400,000 it needs in the coming years to improve security in its 86 vehicles.

The company was among the first to begin installing CCTV in its cars when it piloted the spy in the cab' scheme in 2004 to see if it would deter drunken antics and assaults on drivers.

Meanwhile, Tong and Euro Private Hire, based in Tong Street, Bradford, has tested various camera systems in its cars and today announced it had struck a deal with Cab CCTV, a vehicle camera specialist based in the south of England.

Ken Ives, of Tong and Euro Private Hire, said: "We have found a suitable product which is currently installed in one of our vehicles for driver and passenger safety. We have been testing it for a couple of days now to see if we want it in our other cars.

"It's a visible camera, not hidden, and it covers all five seats.

"It's a constant recording with its own internal battery. It's connected to the ignition and it recharges through the car battery.

"It works 24/7, but it only becomes fully active when you turn the ignition. When you are not in the car, it only reacts to movement, so it would only record when it senses movement when the car is parked overnight.

"We are going to get it in all our cars. We are getting the drivers together to organise how we can install it gradually over the next six months.

"We have 60 vehicles at the moment. The system has been designed purely for taxis, trucks and vans, so it's ideal.

"It costs £750 for each vehicle, but we have got a way of doing it through a three-year lease, so it works out at £6 a week to lease the equipment, with a final payment. It's more manageable than buying it outright."

Mr Ives said the system would reassure drivers and act as a deterrent to potentially-aggressive passengers.

One of the businessmen looking to benefit from the increasing demand for in-car CCTV is Saleem Javed, managing director of Quadtronics Worldwide, in Keighley Road, Frizinghall.

He said: "Our main line is CCTV and Bradford's taxi drivers need security, so we are looking to meet that demand.

"You hear high prices quoted for CCTV to be installed in taxis, but I am going to be different.

"I am looking to do deals because my dad was a taxi driver and I know how hard it can be to earn a living. They see a figure of £1,000 and it looks a lot. I am willing to come up with a policy where they can rent the system off me.

"The big businesses can probably pay up front, but the smaller ones can lease it out. I am willing to help them.

"Some of the machines you hear mentioned only take pictures every 30 minutes, but the system we have got is continuous, with a digital recording on the hard drive.

"It can provide up to four cameras in a vehicle and the machine we are using is designed specifically for vehicles, so the bumps in the road do not affect the hard drive."

Quadtronics Worldwide deals with six taxi companies in Leeds and is now expecting more custom in Bradford.

The biggest in Bradford, Girlington Taxis, said it was taking security seriously.

The company has installed GPS tracking systems in every one of its 130 vehicles at a cost of more than £100,000. If the driver presses a panic button in his cab, a buzzer sounds in the head office and the location of the taxi can be identified by a tracking system.

The system is also designed to make the process of allocating cars to jobs more efficient.

Yasser Iqbal, owner of the company, said: "We take our responsibility seriously and are trying to make changes that other operators will follow. About ten of our drivers have paid for CCTV themselves."