The real identity of an underground graffiti artist who had a year-long feud with stencil artist Banksy in Camden has been revealed, a week after his death.

King Robbo, whose true identity was kept secret from the public for nearly three decades, has been named as John Robertson following his death aged 45 on Thursday last week.

He had been in a vegetative state since he was found lying in the street outside his King’s Cross flat with head injuries in April 2011.

Yesterday, St Pancras Coroners’ Court, which is set to open an inquest into King Robbo’s death, confirmed his real name as John Robertson.

He made global headlines in 2009 when world-famous stencil artist Banksy defaced one of his most historic works on a wall beside Regent’s Canal, beneath the British Transport Police headquarters in Camden Road, Camden Town.

This led to a series of tit-for-tat overpaintings from the two artists on the wall, originally sprayed by King Robbo in 1984, over the following year.

Graffiti artist Doze, 48, a close friend and one of the founders of King Robbo’s original graffiti crew, said: “He’s probably the most prolific and respected British graffiti artist ever.

“The feud will go down as one of the most important times in modern art. Graffiti is now recognised and talked about in the art world whereas previously it was criminalised.”

King Robbo’s death was announced by his crew Team Robbo on their website last week and was followed by a tribute on Banksy’s website which read: “ROBBO WRH WD PFB – R.I.P”.

The feud with Banksy, which brought King Robbo out of retirement, became the subject of a Channel 4 documentary filmed shortly before his head injury.

Banksy publicly objected to the programme, Graffiti Wars, saying it inferred he might have had something to do with his rival’s accident, which the broadcaster denied.

King Robbo, who is survived by his three children, passed away at a neurological centre in Hertfordshire.

A fundraising auction arranged by Team Robbo in September 2011 enabled his family to move him to the centre two years ago.

It is understood he was unable to move or speak and required 24-hour care.

“I wasn’t very happy with visiting,” said Doze. “I’d rather just remember him as he was. It’s quite traumatic, when you’ve got someone you’re so close to, to see them like that.”

Following the feud with Banksy, during which King Robbo defaced a number of Banksy works across Camden, Haringey and Islington, the graffiti artist’s profile grew and he was offered his first solo exhibitions.

Days before a major Team Robbo exhibition in Shoreditch, he was put into an induced coma after being found unconscious outside his flat with head injuries.

The causes of his injuries remain unknown but police concluded there were no suspicious circumstances.

During his career, King Robbo, like Banksy, was keen to keep his identity secret because he “knew the press would love it”, according to Doze, who insists his friend was victorious in the duel with Banksy.

“Banksy probably didn’t expect the backing and the following that we got with the Team Robbo thing,” he said. “It’s gone worldwide. I just don’t think he expected Robbo to come out on top.”

He added: “Since John passed away there’s been stuff painted in Dubai, Canada and Holland. People painting things all over the world as a tribute.

“He always said, ‘This is not just about me. This is to show people who the original pioneers are and that we won’t be forgotten.’”