A crime-fighting helicopter used to bring dozens of Bradford rioters to justice has reached a three-year milestone.

West Yorkshire Police's helicopter Explorer was launched in February 2001 and has completed almost 10,000 missions.

During the 2001 riots the helicopter was used to film the trouble from the sky and down-loaded the images to police commanders leading the operation.

Film captured from the helicopter has been used as evidence to convict dozens of rioters.

John Whittaker, West Yorkshire Police's head of air support, said the work done by the helicopter during the riots had been invaluable and had helped develop the service it provides to the force.

"But we couldn't send the commanders the ground perspective," he said. "That was a lesson we learned.

"Now we can receive pictures from cameras on the ground and, acting like a big aerial in the sky, send both pictures to the commanders who can put both the stories together.

"We flew continuously for several hours, stopping only to refuel.

"On a ten-hour shift, one of our pilots flew for seven hours."

He said it was hoped the helicopter would be available to offer 24-hour cover to the force by April 2005.

He said: "One of the helicopter's massive benefits is its capability for searching.

"In a Home Office experiment various search targets were laid out which were all found within 12 minutes by a police helicopter.

"Those on foot took 454 hours."

Explorer cost £3.3 million and has no tail rotor, making it 50 per cent quieter than the previous police aircraft, 11 per cent more powerful and with a vertical take-off and landing ability.

To assist with searches and public order situations, a 30 million-candle spotlight can light up an area as wide as two football fields from 500 ft above.

During the night, the thermal imaging camera shows up heat differences, which can help pick out a suspect.

Mr Whittaker said: "If you were flying over a field and someone was camouflaged in the same colour, officers could switch to thermal imaging and the shape would stand out as clearly human."

Up to the beginning of February this year, the helicopter had flown for 3,368 hours, spending an average of three hours 18 minutes a day in the air.

Chief Superintendent Dick Rothwell, of West Yorkshire Police's operations support, said: "I am thrilled with the helicopter's performance.

"It has achieved so much since its first flight three years ago. It is a tremendous yet vital crime-fighting tool which continues to give assistance to divisions throughout West Yorkshire."