A high-performance sports car which crashed into a tree killing a 26-year-old Ilkley woman could have been doing more than 50 mph, according to an police accident investigator.

PC Mark Lingard had initially declined to give a speed for Scott Dry's TVR Griffith 500 when he investigated the fatal crash, but in response to a defence expert's calculations he now estimated that it could have been travelling at 51mph when the driver lost control.

Rachel Scantlebury, of Parish Ghyll Drive, had been sitting on the lap of passenger John Oddy when the two-seater TVR spun out of control and smashed into a tree at the junction of Queens Road and Princess Road in July 2004.

Dry, 42, of Westwood Mount, Ilkley, has denied causing Miss Scantlebury's death by dangerous driving and a jury at Bradford Crown Court yesterday heard the disputed crash theories.

"It is my opinion that as the driver has come round the bend he's either applied the accelerator very harshly or steered to the right very harshly or a combination of both,'' said PC Lingard.

The officer said the tyre markings on the road indicated the driver had then applied heavy braking which had locked the front wheels.

PC Lingard said the reference to harsh acceleration or steering did not mean merely accidental or slight and he rejected a suggestion by Dry's barrister Andrew Stubbs that the TVR was "unforgiving''.

The officer explained how some of the tyre marks left by the TVR stretched up to 54 metres and the jury heard it had been calculated that the car was travelling at 24mph when it struck the tree.

"Fifty-four metres is a heck of a distance to still hit the tree at 24mph,'' said PC Lingard.

PC Lingard explained he had been reluctant to calculate a speed because there were too many variables, but after a defence expert's report suggested a possible speed of between 38 and 46.8mph the officer made some calculations.

The jury were also shown video footage of skid tests carried out on the road.

The officer said his calculations had produced a speed of 51.62mph, but it could be as high as 58mph.

PC Lingard said the method used by the defence expert to get a speed of 38mph was "just wrong''.

Under cross-examination PC Lingard accepted he could not prove the TVR was doing more than 46mph when it lost control and that accident investigation was not an exact science.

The trial continues.