An inventor suing the BBC for £3.7m says he can't think properly now due to brain damage suffered whilst acting as a human crash-test dummy for a TV science show.
Jem Stansfield says he sustained life-changing injuries while filming an episode of BBC popular science show Bang Goes the Theory, during which he was strapped into a specially designed rig and catapulted along a track and into a metal pole to mimic the effect of hitting a lamp-post in a car.
Mr Stansfield, who has a degree in aeronautics from Bristol University, is known for his inventions, which include 'Spider-Man style' climbing gloves made from vacuum cleaners and boots that walk on water, for which he won a New Scientist prize.
But his lawyers told London's High Court today that since filming the episode he cannot think properly because 'prolonged intellectual activity' sets off a cascade of symptoms in his damaged brain.
Stansfield told the judge that in the aftermath of the staged crashes, his memory was so badly affected he couldn't even remember his lines.
'The main thing that was noticeable afterwards was my ability to remember my pieces to camera,' he said.
'Everybody was commenting that it was really unusual that I couldn't remember my lines.
'That's not like me. It was very unusual.'
Jem Stansfield is pictured outside the Royal Courts of Justice London today
Jem Stansfield, above, says he sustained life-changing injuries while filming an episode of BBC popular science show Bang Goes the Theory
Mr Stansfield, who has a degree in aeronautics from Bristol University, is known for his inventions
The engineer is suing for £3.7m, claiming the injuries robbed him of his 'stellar' career and, but for his disability, he could have gone on to earn as much as Top Gear presenters Jeremy Clarkson, James May and Richard Hammond
But despite agreeing to make a payout, the BBC is hotly contesting the amount in damages which the presenter should get.
Today, he attended the High Court in London, masked and in a jumper over shirt combo, where a full trial of his compensation battle kicked off before senior judge, Mrs Justice Yip.
Marcus Grant, for Mr Stansfield told Mrs Justice Yip that the crash tests, including a set performed in reverse to test the safety of a child car seat facing backwards, caused injury to Mr Stansfield 'right at the heart of the brain'.
There was also damage to the nerves connecting his eyes, ears and nose to his brain, the barrister said.
He has since suffered 'profound sleep disturbance' and 'disturbance to his memory,' as well as having the 'processing speed' of his brain 'strikingly impaired,' said Mr Grant.
There has been a 'decomposition of the function of the brain' due to the repeated crash tests the lawyer said, adding that Mr Stansfield's symptoms 'turn on and off' and vary in severity.
A clip of him on the show shows Mr Stansfield, who was strapped into a specially designed cart and catapulted into a fake lamppost, pulled forwards and backwards by the contraption
It is when Mr Stansfield attempts to use his formerly brilliant brain for 'prolonged intellectual activity' that the effects of the injury are most noticeable the barrister told the judge, adding, 'anything that calls on his brain reserve will aggravate his symptoms'.
Mr Stansfield gave evidence to the court this afternoon.
He went to see his GP on the day after the final tests, telling the doctor of not feeling himself and his anxiety at possibly losing mental capacity, as it was vital for work.
He was told to take painkillers, but then went to A&E a couple of days later, when he complained of suffering bad headaches and was x-rayed in case his neck was broken.
Mr Stansfield told the judge that, in speaking to colleagues soon afterwards, he had probably downplayed how bad he felt at the time.
'I always prided myself on being very tough and I had a reputation for being tough and resilient,' he said.
'I wouldn't have gone to hospital unless something was really bad, for sure..'
Jem Stansfield, 46, appeared as part of a crash simulation on his show, BBC One's Bang Goes The Theory in 2014
Mr Stansfield's injuries occurred during a second series episode of the popular show, which the BBC billed as: 'Engineer Jem becomes a crash test dummy to discover how much g-force his body can take.'
The judge, Mrs Justice Yip, has already seen footage of the tests, which took place on two days in February 2013.
In the broadcast footage, Mr Stansfield declares himself 'a little nervous' and adds: 'tests make me confident I will walk away, but what we don't know is how my body will behave'.
His cart is seen slamming into the metal pole and his head jerking back before he announces: 'there's definitely an impact'.
Court documents reveal that the stunt left him with 'soft tissue injury to the structures around the spine' as well as a 'subtle brain injury' caused by the shock 'the repeated acceleration/deceleration forces generated by the crash-tests'.
Other alleged effects of the accident include dizziness, psychological damage and a possible carotid or vascular injury, and medics have described his condition as 'complex'.
Lawyers on both sides accept he is a 'very unwell man' and his own doctors say his current chances of further significant recovery are 'poor'.
His legal team claim that without the effects of the crash testing he could now be earning up to £500,000 per year, and that he had dazzling prospects as his talents spanned creativity, writing, presenting and engineering.
But for the injury, he would have ended up carving out his own unique niche, breaking into the US market and developing lucrative roles as a 'brand ambassador'.
His lawyers say he would have been earning at the same level as top TV stars, adding that 'Jeremy Clarkson, James May and Richard Hammond...may provide a good source of comparison'.
The issue of liability in the case has already been settled, with the BBC agreeing to pay Mr Stansfield two-thirds of the full value of his claim after a discount for his own 'contributory negligence'.
But contesting the amount claimed, BBC barrister Jonathan Watt-Pringle QC says the corporation is 'requiring him to prove that the unusual array of symptoms of which he complains arose from disabling organic brain damage, vestibular or whiplash injuries and/or disabling psychological injuries in the crash tests'.
The trial continues.