A LEADING Edinburgh Festival Fringe venue is embroiled in a drama of its own, with the sudden mystery departure of one of its key artistic figures.

Summerhall, formerly the Royal Dick Vet School, has quickly become one of the key attractions of the world's biggest arts festival. It has sold a record number of tickets this year for its eclectic mix of theatre, art, dance, children's and music events.

One of the keys to its critical success has been its range of contemporary art exhibitions staged throughout the extensive, 500-room building, which have been created by curator and artist Paul Robertson.

But Robertson is now taking legal action against the Summerhall management after he was suddenly asked to leave his job and the vast building, where he has lived for the past year.

The reasons for his sudden departure are not yet clear, but Robertson's lawyers are understood to have lodged a series of claims against the venue's management. His work has included staging more than 70 shows at the venue in the past three years.

One source said: "It is such a shame. The visual arts shows are one of the strengths of the venue."

One show arranged by ­Robertson has now been closed, a Summerhall spokeswoman confirmed. The permanent ­exhibition Phenotype Genotype included work belonging to the curator and he has removed the works from display.

In addition to the ticket sales success, the building has won a clutch of awards for its theatrical shows. Last year, it sold more than 36,000 tickets. The spokeswoman added: "Paul Robertson is planning to move on from Summerhall this year. A notice period has not been finalised."

The venue would not comment on legal proceedings or how Robertson came to leave his work.

This year's exhibitions include Susan Hiller's Re-Sounding, the Deluxx Fluxx Arcade in the basement, and Genesis and Lady Jaye Breyer P-Orridge's Life as a Cheap Suitcase.

Last year, the visual art shows featured one of the talking points of the Fringe, Gregor Schneider's Susser Duft, which involved a room full of naked black men in a basement area of the large venue, and exhibitions by Fiona Banner, Michael Nyman, and many others.

Robertson had worked for the building since 2011 when it first opened as an arts complex, making its name on the Fringe with Hotel Medea in the same year.

It is not only a Fringe venue, as it is open throughout the year with visual art shows, a bar and other facilities. It also holds the extensive Richard Demarco Archive and Art Collection.

Last year, the venue was involved in a tax dispute with Her Majesty's Revenue and Customs (HMRC).

HMRC lodged a petition with Edinburgh Sheriff Court in early August last year asking for an order that the company that runs the venue, Summerhall Management Ltd, be wound up and for the court to appoint a liquidator.

Last month, it emerged the venue had owed more than £200,000, but Summerhall has subsequently resolved its issues with HMRC.

Robertson declined to comment.