FORMULA One-style technology from a car’s airbag was used in the UK for the first time to help prosecute an Oxford driver responsible for a fatal crash.

Investigators were able to pinpoint the moment Anthony Reilly took his foot off the accelerator and braked before hitting queuing traffic on the M40.

Hazel Russell, 78, was a back-seat passenger in a Peugeot 207 hit “at about 70mph” by Reilly.

She died from her injuries.

Data was recovered from the airbag control module in Reilly’s Chrysler 300 after American courts forced domestic manufacturers to make such information available.

Reilly, 55, of Yeftly Drive, Littlemore, struck the Peugeot at about 9.45am on April 1 on the southbound carriageway close to the Chiltern cutting near Lewknor.

Data from the airbag revealed he lifted his foot off the accelerator 0.5 seconds before impact and began braking 0.3 seconds before.

Reilly earlier admitted causing death by careless driving.

Speaking after the landmark case at Oxford Crown Court on Monday, prosecutor Brian Payne said: “As far as police and the CPS are concerned this is the first time we have been able to use airbag data-management systems to assist in a prosecution.

“Access is only limited to vehicles of American manufacture at present.

“It means you can tell what the driver’s feet were doing in terms of control of the vehicle and, importantly in this case, it allowed us to say that he didn’t apply the brakes until 0.3 of a second before impact, showing he hadn’t appreciated there was a hazard in front of him and that it was a hazard he should have been able to see for a number of seconds.”

The court heard former Rolls Royce engineering trainee Reilly was travelling at 74mph five seconds before the crash. Mr Payne told the court the father-of-one should have been able to see the mounting traffic ahead for as much as 12 seconds or 400m.

He said: “The prosecution case is the level of carelessness falls at the most severe end, not far below that of dangerous driving.

“The Chrysler was to all intents and purposes travelling at the same constant, or nearly constant, speed until half a second before impact and from that the Crown derives the assertion there was in front of Mr Reilly a clearly visible developing hazard he could have seen for an appreciable period of time beforehand but failed so to do and was thus careless, but careless to a high degree.”

Jamie de Burgos, defending, said: “Now, following the shock of the accident, he has no, or little, recollection of what actually happened.”

Judge Gordon Risius said the Chrysler was doing “about 70mph" on impact.

Reilly was given a nine-month suspended prison term and 200 hours’ unpaid work. He was also banned from driving for two years and ordered to pay £1,200 costs.