A London street artist is being investigated by police after being accused of “shamelessly defacing” an historic beauty spot in Malta which featured on Game of Thrones.

Colourful graffiti bearing Nathan Bowen’s distinctive graphic style has been attacked by the island’s tourist board as “a clear act of vandalism”.

The three large cartoon figures were signed with the artist’s name.

A spokeswoman for the local police today told the Standard: “There is an investigation. We are wanting to speak to him. We have tried, but we have not been able to find him.

“We are actively looking for him.”

The 30-year-old, a Central St Martins College fine art graduate who once appeared on the Apprentice, is also facing the fury of residents.

The vivid paintings, on rocks near Roman tombs and a 17th-century bridge built by the Knights of Saint John, were spotted by a resident hiking at the weekend.

The spot has become a tourist mecca after being used as the backdrop for Daenerys and Drogo’s wedding scene in the first season of the smash hit HBO show.

Joe Muscat, the chief executive of the Gozo Tourism Association, condemned the “eco-vandalism”. He said: “The graffiti paintings splashed across the Xlendi Kantra Valley, are a clear act of vandalism, tarnishing the natural beauty of one of the islands’ picturesque rural areas.”

Outraged locals have flooded the artist’s social media sites. One wrote: “Well done Nathan Bowen for defacing one of our island’s most important heritage sites with your graffiti. What might have been acceptable under a bridge in Croydon or Brixton was not acceptable in this place.”

Some suggested the artist should be forced to clean the rockface by hand or be banned from the island while others called for his arrest.

Bowen’s art sells for up to £550 online. He appeared on a 2012 episode of the Apprentice where the contestants had to sell his work from a pop-up stall. He has not responded to requests to comment.

At the family home in Catford, south London, his mother told the Standard: “I don’t even know he had been to Malta. I’m going to call him right away.”