A PENSIONER told a jury he had no idea a device fitted to his car jammed police speed guns.

Eric Craggs said he had only wanted equipment installed to his Aston Martin that warned of speed cameras ahead.

Teesside Crown Court heard how the 68-year-old had booked his car in for service at Stratstone Aston Martin garage in Houghton-le-Spring in 2009.

Mr Craggs said he already had a device in his car which warned when he was approaching speed cameras, which had previously been installed in his wife's Toyota.

However, he said the couple disliked the system because it was also triggered by traffic lights.

Giving evidence at the start of the defence case, Mr Craggs said: "I said I wanted a device like this (the one already fitted) that did not talk to me at traffic lights - a device fitted that told me when I was approaching cameras."

The court heard that when he collected the car, the garage had installed two devices.

Mr Craggs said he assumed they were to detect different types of cameras.

Asked if he had intended for a jamming device to be installed, he said: "I had no intention of that being fitted whatsoever."

Andrew Walker, prosecuting, suggested the reason the defendant had not had the second device repaired when he thought it had broken was because he knew it was a jammer and knew it was working.

In response, Mr Craggs said the device would screech when he pulled up close to objects.

"I run a very large business," he added.

"I make decisions and move on, I decided I didn't like that device, I decided I didn't want it repaired."

The defendant said nobody at the garage had explained what the second device did and he had never received an instruction manual for it.

Asked about an invoice he received for the equipment, Mr Craggs said: "It doesn't say 'laser jamming system', it doesn't say 'laser diffuser', it doesn't say 'this is illegal'."

Mr Craggs' trial has heard that twice his Aston Martin evaded detection in Stockton when a Cleveland police officer, PC Lorraine Williams, attempted to check his speed with her equipment displaying an 'error' message.

Mr Craggs, 68, of Junction Road, Norton, Stockton, denies doing acts intended to pervert the course of public justice between July 15, 2009, and August 12, 2013. The trial continues.