A 91-year-old motorist from Barnet had been at the wheel non-stop for 16 hours before killing a young chef in a head-on collision while driving on the wrong side of the road.

Billy Warwick-Jones, 20, died after a Ford Focus ploughed into his motorbike at a combined head-on collision speed of 100mph on the A3 near New Malden, Surrey, shortly before 6am on August 29 last year, an inquest heard.

Mr Warwick-Jones was struck by the elderly motorist, named in court only as Mr Woods, who had been driving down the wrong way down the main road for up to 14 miles.

A police probe found Mr Woods may have been suffering from confusion and delirium caused by a urinary tract infection.

While waiting to determine whether to charge him with causing death by dangerous driving, Mr Woods died of Covid-19 in January this year.

In the four months after the crash, he was not arrested nor banned from driving - although he did hand his licence in to the DVLA at some point during that period.

Area Coroner Lydia Brown said she had "grave concerns" about why a man with a history of urinary tract infections, which can cause sudden confusion in elderly people, was allowed to continue to drive.

She said she will be writing to the DVLA, the Minister for Transport, the General Medical Council, and the GP in question in her report to prevent future deaths in which a response will be required within 56 days.

Mr Warwick-Jones' family are calling for a law change so that over 70s have to be retested every five years.

On the day of the motorcyclist's death, friends said they had met him at around 2.30am in Hyde Park, central London, as he was often awake during the night. Two witnesses say they saw him drink a can of Stella Artois which was unfinished by the time he went home at around 4am.

A toxicology report found Mr Warwick-Jones was just over the legal limit of alcohol and cocaine, but witnesses say that he was not riding recklessly and police confirmed this was not a contributing factor to his death.

Witnesses say the incident happened at just around dawn at around 5.40am when the rider was driving southbound near the junction of Coombe Road in Kingston-upon-Thames.

Due to the slight bend in the road, officers say Me Warwick-Jones is likely to not have been aware of the vehicle being on the wrong side of the road and had limited time to think when the incident occurred.

The investigator officer said the "last thing you would expect or encounter is a vehicle travelling towards you on the same carriageway".

The court heard an off-duty paramedic stopped her car on the way to work and stopped on the carriageway to help but it soon became apparent that Mr Warwick-Jones could not be saved.

Will Holland, a police officer driving northbound in a marked vehicle in the area, attempted to coordinate a response before the crash occurred but a helicopter was not available, the inquest was told.

He said he had also completed a dynamic risk assessment and found he could not drive ahead to warn other road users, was concerned the use of blue lights would have caused the driver to speed up and drive even more dangerously, and so followed the car.

Inspector Holland said: "There was a vehicle slowing with their hazard lights on so I felt able to stop and begin the initial triage.

"As I approached, I could see his eyes were closed and I could not see his chest rising and falling.

"Ahead I saw a female in a green London Ambulance Service uniform stop her car and help. She commenced CPR.

"The driver in the Ford Focus attempted to then start the vehicle. The male appeared elderly, incoherent, and seemingly unaware of the tragic incident around us. I took possession of his car key."

Detective Sergeant James Hathaway, from the Met Police collision investigation unit of south west London, gave live evidence at West London Coroner's Court and said they were able to determine Mr Warwick-Jones' movements quickly.

He said: "More complex were the movements of Mr Woods prior to the collision. Mr Woods was a 91-year-old male at the time of the collision. He lived in Barnet and didn't seem to have any plausible reason why he would be in that area, in southwest London at that time in the morning.

"It became apparent he lived alone, and was due to visit family, his daughter on the Friday evening. He had never arrived. It was believed by the family he decided to not come and didn't look further as to why he didn't arrive.

"We looked at automatic plate reading and these suggest Mr Woods had been driving around for approximately 16 hours with no obvious gap in the movement of his vehicle prior to the collision."

He added: "The doctor who briefly treated and saw Mr Woods at the scene described him as being in a confused state and he was found to be suffering from a urinary tract infection at the time of the collision.

"We tried to interview Mr Woods in the coming weeks and months following the collision but he was never medically well enough for us to interview him - his cognitive ability was not there."

Police learned Mr Woods passed away at Barnet General Hospital on January 4 after contracting Covid.

The Coroner returned a conclusion that Billy died of a road traffic collision with multiple injuries and it is likely he died almost instantaneously "without any pain". He was pronounced dead at 6.36am.

Mr Warwick-Jones mother Kelly said: "Billy did not have a bad bone in him. He was so caring and thoughtful towards others."

His sister, Amy, added: "Billy was the biggest character and would light up any room. He could honestly have been a comedian.

"What happened is so unfair. He didn't deserve this. He never got half the things he would have achieved. I believe he will always live on through my children who he loved more than life itself."