Karen Mirza & Brad Butler, artists: 'We've worked together for 19 years, but have an open relationship'

Karen Wright meets the artistic collaborators Karen Mirza and Brad Butler in their studio on Bethnal Green Road, east London

Finding the studio of artistic collaborators Karen Mirza and Brad Butler is a challenge. Amid the street market and colourful clothes shops on Bethnal Green Road, east London, a discreet doorway opens to a vertiginous flight of stairs. On the first floor at the back is the studio for No.w.here, founded in 2004 in the duo's garage in Kilburn, and moved here in 2010. It is a space for artists to produce their films with a lab still capable of developing analogue prints, a yearly subscription allows access to the equipment – Mirza says proudly "about 50 films have been made in this space in the last year" – and there is an atmosphere of quiet intention in the room.

On the street side is a bright simple room where discussions of projects takes place. Around the wall a timeline painted in blackboard paint festooned with Post-it notes, chronicles the four years they have been here. Up another two flights of space a whitewashed room decorated with the pair's neon slogans, Sixties furniture and books gives the space a comfortable atmosphere. This is home to the many screenings that the pair host. Mirza admits that much of her time is spent in administration now – one of the reasons they have invested in a small space in Istanbul, where there is more room for their own creative process to be discussed.

Mirza is very much the spokesperson. I ask whether they are a couple as well as collaborators and a discussion ensues. "We have worked together for 19 years since we both left the Royal College of Art. We have an open relationship" is their consensual answer. It is clear they both love Bethnal Green Road and admit it is a fight holding the space against the tide of gentrification along the road. Butler points out that the road is now sandwiched between two expensive apartment buildings.

When I ask who inspires them as artists, Mizra says Hans Haacke and writer Ursula K Le Guin. Butler says, "Well, [philosopher] Judith Butler's words [from her book Frames of War] are tattooed on my arm." Recently their work has been increasingly acknowledged. They are the only British artists nominated for the Artes Mundi prize and are included in the current group show at the Hayward in London.

Explaining their practice is difficult though. Since 2009 the duo have been developing a body of work called The Museum of Non Participation (Mirza's deceptively simple explanation of this is "artwork to disrupt"). Video and neon may be usual practice, but social engagement, providing space, curating and publishing does not frequently enter an artists' list of mediums. Nor does Butler's description, "We are interested in risk-taking."

When I comment on Mizra's gold necklace, a simple piece saying "disobey", she smiles. "My family are warriors – Afghanistan and Indian Muslim." "Mine are teachers," says Butler.

Artes Mundi will be awarded in January. Mirza and Butler are included in Mirrorcity, Hayward Gallery, London SE1 (020 7960 4200) to 4 January