A man left paralysed after falling on his head during a mountain biking course in the Surrey Hills is suing the instructor for £4m in damages.

The Telegraph reports that Asif Ahmed landed on the front of his head, just above the forehead, after hitting “what looked like a clumpy, grassy piece of ground” during a £79 beginners’ skills course on Holmbury Hill in March 2012. He now faces the rest of his life in a wheelchair.

Frank Burton QC, representing Ahmed, said the incident had occurred “during a descent described variously as a slope, gully, drop off or bombhole at part of the route known as Barry Knows Best”.

Ahmed alleges that Leon MacLean used a “lazy form of teaching” and was guilty of “woefully inadequate” supervision.

MacLean denied he “progressed this group too fast” and said Ahmed twice went down the wrong part of the track.

Burton told the High Court that Ahmed was “not a thrill seeker”. A regular gym-goer and cricketer before his accident, he was described as an experienced cyclist, but a novice on rough terrain and descents.

“A mountain bike rider who is on a course for beginners and is a novice should not be catastrophically injured in the first 75 minutes of an introductory training course.

“A novice rider on a first training course should expect the instructor to pick the terrain, to pick the course, to pick the method of training so the risk is minimised, so this accident should not have occurred.

“The accident occurred because of defective instruction and defective teaching.”

Ahmed believed he had been instructed ‘to descend the gully at speed and without braking’.

MacLean, who is also a teacher, said that Ahmed rode down the “wrong part of the track” once and then repeated the error.

“I am 100 per cent sure he made the same mistake twice,” he said. “I was surprised at the time. It has been on my mind for four-and-a-half years and I am absolutely positive it happened.”

Tim Horlock QC said MacLean was “a careful and considerate instructor,” adding: “He is the very opposite from the picture that is sought to be painted of a cavalier or gung-ho, authoritative or rushed, instructor.”

Horlock said the group had not been rushed and that Ahmed had known he could have walked instead of ridden at any point. He also claimed that Ahmed’s mountain biking experience ‘was significantly greater than one might have been led to believe’.

“There was nothing unreasonable about permitting Mr Ahmed, a mountain biker of 12 years’ experience, to have a run down the slope once, or more than once.”

Mr Justice Baker reserved his judgment to a later date.