A home is typically a shelter from the outside world but a new generation of property owner is bringing the exterior indoors: the market for graphic and street art, now part of every metropolitan centre, is booming. Works first seen fly-postered, stickered, stencilled or graffitied along side roads and up back alleys are increasingly offered by edgier galleries and are attracting the attention of large auction houses, catering to a market that has blossomed in the wake of the hype surrounding controversial urban artist Banksy – whose pieces now sell for upwards of £50,000 and who counts the likes of actor Brad Pitt and singer Christina Aguilera among his collectors. This month |London auction house Bonhams, for instance, held its first sale devoted entirely to urban art, with spring seeing smaller galleries also hosting shows by the likes of Blek Le Rat and David Choe, both respected (if sometimes identity-protecting) names in the street art (under)world.

The works of such artists are typically produced in print editions of between 50 and 200 and sell out quickly – an edition of 200 by the artist D*Face released last month sold out online in just eight minutes. And certainly their investment value is, for some buyers, part of their appeal.