PIONEERING graffiti artist and Banksy rival “King Robbo” died of pneumonia three years after slipping into a coma after fracturing his skull falling down the stairs in King’s Cross, an inquest has heard. 

The trailblazer, whose real name was John Robertson, rose to fame in the 1980s on the streets of north London and became instrumental in developing the European graffiti scene. 

Many of his artworks on his old stamping grounds, like Regent’s Canal, remained untouched for more than 20 years, a rare mark of respect from the graffiti community. 

The father of three, who grew up in Islington, was spotted by passers-by lying in a pool of blood outside his flat in Calshot Street in April, 2011. 

The underground artist, who had kept his identity a closely guarded secret, was placed in a medically induced coma but remained in a vegetative state.

The founder of the Tone Deaf Krew – a well-known artists collective – died of pneumonia aged 44 at a neurological hospital in Hertfordshire in July, St Pancras Coroner’s Court heard yesterday (Wednesday). 

But the cause of his accident remains a mystery after senior coroner Mary Hassell ruled that there was “not enough evidence” to determine why it took place. 

At the time rumours circulated that Mr Robertson had fallen while trying to get into a first-floor flat after locking himself out at 2am.

Ms Hassell told the inquest, which was not attended by any family members, that witness Peter Watt had reported seeing Mr Robertson around 2am on April 2 “at the top of 10 stairs texting on his mobile”.

Black cab passenger Louisa Green said in a statement that she spotted him 20 minutes later “lying on the ground at the bottom of the steps with blood around his head” and called an ambulance.  

“Police made further extensive inquiries including house to house,” Ms Hassell told the inquest. 

“All that was gained was that Mr Robertson had been drinking earlier in the evening. Mr Robertson’s incident was regarded as being unexplained. There was no suggestion of foul play.”

Paramedics from the London Ambulance Service took the artist to the Royal London Hospital where he underwent surgery for a fractured skull. He was later transferred to the Whittington Hospital in June for four months where doctors noted that he had begun to open his eyes and could wiggle his toes on command. 

But after being transferred to the Royal Hospital for Neuro-disability in Putney, Dr Kudret Yelden diagnosed him as being “in a vegetative state second to traumatic brain injury” and that he made little progress. 

In March this year he was taken to the Gardens and Jacobs Neurological Centres in Sawbridgeworth, Hertfordshire, where he passed away on July 31 after developing pneumonia. 

Recording an open verdict, Ms Hassell said: “I have no hesitation in saying that Mr Robertson died as a result of the long-term traumatic brain injury that he suffered in 2011. However, I have scant evidence as to how that brain injury was sustained. He was found at the bottom of the flight steps. It may be that he simply fell down that flight but I have no evidence.”

Three months after Mr Robertson’s death, a Channel 4 documentary, Graffiti Wars, was aired featuring his long-running feud with Banksy. The pair had become involved in a public clash in a bar in Old Street which resulted in Banksy painting a figure of a man putting wallpaper over a 1985 Robbo mural on the Regent’s Canal that had been left untouched for more than 20 years – even by council clean-up teams. 

It sparked some tongue-in-cheek tit-for-tat res­ponses between the two tagging Titans.

Robbo told the New Journal at the time: “He painted over my piece. There are plenty of walls we could both use. There was no need to do this.”

Seven months after his accident, on the disputed patch of wall under the canal a piece of graffiti art to Robbo appeared featuring a drawing of a crown –  some believe it was a tribute from Banksy. 

Mr Robertson is survived by his partner, two daughters and a son.