The van driver who accidentally knocked down and killed boxer Gary Mason failed an eye test after he was arrested by police following the fatal collision.

Piero Zanelli, 44, from Purley, who knocked the former British heavyweight champion Mason off his bike in Wallington on January 6 last year, is now being sued by Mason's family over his death.

Zanelli collided with Mason as the driver turned right into Sandy Lane South from Woodcote Road shortly after 6am.

He was stopped at the scene, and arrested by police on suspicion of causing death by dangerous driving.

Richard Clark, from Hampton Traffic Garage, that investigated the crash, said Mr Zanelli’s eyesight was tested by police in daylight on the day of the collision, a test which he had failed.

But an independent assessment at an opticians within the next fortnight found that his eyesight was at the correct level for driving.

Mr Zanelli today told an inquest at Croydon Coroner's Court the thud of Mason hitting his windscreen was the first he knew about the accident.

He said: "It was all in one go. I didn't see anybody [..] there was a thump, the windscreen shattered."

Mason hit the windscreen before hitting the ground, as his bike was dragged under the wheels of the van.

He was pronounced dead at the scene.

The inquest heard CCTV showed 60m before the crash, Mr Zanellis' van was travelling between 36 and 41mph, above the 30mph speed limit.

Mr Clark estimated Mr Zanelli was travelling between 25 and 48mph at the time of the collision, and it was likely the driver had not followed the road markings to turn - something common at the junction.

Mr Zanelli told the court he had braked to about 15 to 20mph before turning.

He said he regularly took the turning , and "eight times out of 10″ he would cut across the road markings if the road was clear.

The court heard he would not have been able to tell his speed by the speedometer, as the light was broken.

There was no indication Mason had a front light, and was using a helmet or reflective clothing.

Coroner Roy Palmer recorded a verdict of accidental death.

During the inquest Mr Zanelli apologised to Mr Mason's family for what had happened.

He said: "It has been a year and I haven’t been able to pass on my condolences and I’m truly sorry for what has happened and if I could have avoided the whole thing I would have. I am truly sorry and once again pass on my condolences to the family and friends."

Speaking after the inquest, his sister Paulette Stewart said: "Gary was a wonderful man and father, well loved by all and was taken from us through the reckless driving of Mr Zanelli. We, as a family, will never get over Gary’s death which in our view was clearly avoidable."

Police have not pressed charges against Mr Zanelli.