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Driver using a laser jammer given 8- month prison sentence

On Saturday 19th May, 2018 a Casualty Reduction Officer (CRO) enforcing the speed limits in Dyfed-Powys attempted to measure the speed of a silver Mercedes-Benz S350, registered to a Mr Keith John (65 years old). However, no speed could be obtained from the laser camera used by the CRO.

The CRO was trained to recognise when a speed camera was being interfered with by countermeasure devices and recognising that the error message shown on the device was not normal, the CRO reported the incident to supervisors at Dyfed-Powys Police for further enquiries.

The video recording of the incident was sent for investigation by Steve Callaghan at Road Safety Support (RSS).

Upon investigation, 2 black rectangular objects could be seen fitted to the front of the vehicle, one on each side of the registration plate. The shape and location of these objects are typical for the transmit/receive modules of a laser jammer. The purpose of the jammer is to receive the infra-red light from the camera and to determine how quickly it flashes the laser at the vehicle during the speed measurement.  Once the flash rate is determined, usually within 3 or 4 flashes, the jammer then sends very bright flashes of infra-red light back to the camera that are arranged to confuse it. 

Steve Callaghan examined the video and confirmed that the device seen attached to the vehicle, and the reaction of the camera confirmed that there was a laser jammer device fitted to the car and it had prevented the speed reading.  The camera could be seen to measure the speed of a car immediately before and immediately after the attempt to measure the Mercedes so it was obvious that the camera was working correctly at the time.

PCs Whiles and Jones subsequently visited the home of Mr. John to ascertain what the device was on the front of his vehicle. While at the property, the officers noted that a small van and a VWPolo had the same devices fitted to them. Further enquiries into vehicles registered at the address discovered 2 other VW Polo cars, these were normally used by Mr. John’s wife and daughters.

All 5 vehicles were seized, and on the 1st April 2019 Steve Callaghan, of RSS inspected all 5 vehicles. 

In total, 6 laser jammer systems were recovered from the 5 vehicles.  The Vauxhall van alone having 2 separate laser jamming systems and a radar & laser warning device fitted to it. 

The jammer on the Mercedes was clearly visible at the front of the vehicle in the place it was seen in the enforcement video.  Other components of the jammer were found concealed within the car.  A laser speed camera was used to test whether the jammers interfered with the laser.  At the same time, the warning signals that would be seen and heard by the driver when the laser was used to try to measure the speed of the vehicle were recorded by a video camera.

Steve Callaghan, Forensic Engineer at Road Safety Support said:  

“The police speed enforcement operators in Dyfed Powys police were trained to a very high standard. This allowed the operator in this case to expertly recognise when the laser jammer on Mr John’s car was interfering with the laser he was using.  

While Mr John, as others have done before him, contended that the Blinder jammer can function as a parking sensor, this is a deliberate scam to attempt to confuse the police and courts.  Mr John’s S-class Mercedes, one of the most well-equipped and luxurious cars by reputation and quality, needed no additional device to supplement the excellent parking aids on his car.  

The Blinder jammer is primarily a device used to trick the police into thinking their equipment is defective while the driver using it can speed with impunity. In any case it should be recognised that laser jamming devices are all but useless as a parking sensor. Thankfully this jury was not deceived by that ruse.” 

Mr. John was charged with Perverting the Course of Justice, pleading not guilty, with  is trial held at Merthyr Tydfil Crown Court between 18th-21st May 2021. 

During the trial, Mr. John’s defence was in 4 main strands:

That the laser jammer was a parking sensor and was not bought as a laser jamming system.

He didn’t drive his vehicle at a speed in excess of 60 mph.

Because his vehicle was not being driven at excess speed there was no need to have the jammer set to jam, it was set to position 1, parking sensor, not position 3, the jamming mode.

Steve Callaghan’s opinions were not accepted.


At the end of the trial the jury were apparently not convinced by Mr John’s defence, returning a guilty verdict. 

Inspector Andrew Williams said:

“A tremendous amount of work went into this investigation – firstly in proving that the devices installed on John’s cars were indeed laser speed jammers, and secondly that he had been driving over the limit despite his attempts to avoid being picked up by cameras. 

I would like to thank all involved for their efforts in putting together a strong file of evidence, and overcoming a number of difficulties during the investigation – not least the defendant’s reluctance to provide any information in interview. 

Speed cameras – both fixed and mobile – are there not to frustrate drivers, but for the safety of all road users. By installing devices like this to evade being caught driving at excess speed, John showed a blatant disregard for the law, putting himself and others at risk.”

On the 23rd July, 2021 the Judge sentenced Mr. John to 8 months imprisonment for perverting the course of justice.

Sgt Ian Price, Dyfed Powys Police GoSafe Coordinator said: 

“The offence of speeding in these circumstances would have ordinarily caused a driver to have their driving licence endorsed and a fine of £100 or an educational speed awareness course.

However, when people go to extreme lengths to avoid prosecution in fitting technology to their car that allows them to exceed the speed limit without fear prosecution they not only show an insalubrious attitude towards the judicial system of this country and what It stands for, they also display a complete disdain towards the risk of harm to others where excessive or inappropriate speed are one of the primary causes of killed or serious injury collisions in the UK. The sentence handed out is a lesson to those in society who feel they can cheat the law and pose a real and substantial risk of harm on our roads”. 

Teresa Ciano, GoSafe Partnership Manager said: 

“The majority of road users comply with the legal speed limits and play their part in keeping Welsh roads safe. The minority of motorists who buy and utilise these laser jammers do so to enable them to knowingly travel at high speeds whilst thinking they can evade prosecution. 

We would hope that through the level of evidence presented at this trial and the sentence given will serve as a deterrent for other motorists from attempting to evade justice in this manner. 

Speeding is a choice, fitting a laser jammer is a choice; a choice which Mr. John made to the detriment of safety of all other road users. A choice which has led to the sentence today. 

We would urge all motorists to stand up for slowing down; by doing so you will not only avoid a speeding fine, but you will be making a difference to the safety of our roads.”