Last updated at 17:52 08 October 2007

A scientist escaped a speeding fine after a mobile phone system he devised showed that a police speed camera clocked him at 12mph more than he was going.

The new tracking system, likened to an aircraft's black box, could now be used to challenge the controversial issue of speed cameras.

Dr Phillip Tann was hauled before magistrates after police claimed he was doing 42mph in a 30mph limit but records from his own invention convinced prosecutors he was doing less than the permitted 30mph.

The case has now been discontinued and the 45-year-old technology firm boss said the ruling could open the floodgates for other hapless motorists accused of speeding.

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Central to the accuracy of the system is that it can measure data over distances of less than half a metre compared to traditional GPS devices which work on distances of around five metres.

After a number of pre-trial hearings the Crown Prosecution Service has now told his solicitor, Peter Thubron, that the case is being discontinued and he does not have to attend a planned trial on October 18 at Sunderland Magistrates Court.

Dr Tann, who has been working on the global positioning device for two years was driving through Sunderland collecting road data for the system when he was clocked by a police mobile speed camera.

Knowing his speed was an exact 29.177196mph he did not give it a second thought until he received a letter and fine from Northumbria Police.

Knowing he could prove his speed through the tracking system he has designed he challenged it through the courts.

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The system, which can be installed on a mobile phone, records the location and speed of the handset on a computer database.

The design has already received government funding, with an NStar proof of concept award.

Dr Tann, whose business Autopoietic Systems (Tann Ltd) is based in Birtley, Gateshead, said: "When I received the fine, I checked the database."

"The system I was testing is more accurate than anything else on the market.

It said I was only doing 29.177196mph at that time."

Dr Tann, from South Shields, then turned up to a magistrates hearing with a CD containing his evidence and pleaded not guilty.

He said: "My solicitor, Peter Thubron, stood up and told them the exact speed I was travelling at that time."

"The Crown Prosecution Service requested to view the system and has now agreed that the Autopoietic System was more accurate than the police laser gun."

"I knew when I received the fine I couldn't have been exceeding the limit because I'd seen the van with the camera. So I was surprised to receive a fine.

"The cameras used are not 100 per cent accurate, but my system is."

"It can track a GPS phone within half a metre of where it is, whereas devices currently on the market can, at best, only track a phone within five metres."

"In the past people have had to rely on the accuracy of the police cameras and they can be subject to error but this information can be downloaded as used as proof."

Dr Tann will also be releasing a product this December as an aid to people suffering from such conditions as Alzheimer's Disease and any parents who want to know the location of their child.

Dr Tann added, "With this accuracy we can provide many new services, including sending an alarm if a phone travels outside an area or at a speed greater than 15mph."