Javier Calleja, sought-after by collectors

All the works were sold before the inauguration and there is a waiting list of over 50 collectors, and that is just at this gallery. The same occurs when Calleja exhibits at others such as the Rafael Pérez Hernando (Madrid), Zink (Regensburg) and Nanzuka (Tokyo and Hong Kong). You can't just assume that there will be a waiting list. I'm cautious. I've always said you have to know where you are, and where you are not. One thing is my artistic work, and another is the work I put on the market , he says.

Having a waiting list of collectors can go on forever or might just stop. So I don't think about it. I just carry on working, I know I can do a certain number of paintings a year and that is what there is. I think there comes a time when, if you care too much about the financial side, your standard drops and if you do less, you become lazy, says Calleja, whose works are on display until 28 July.

Gallery owner Juan Pablo Yusto agrees. It is increasingly less important where you are, and more important what you're doing. Javier's work is mainly known through social media. In his case, collectors seek him out instead of the other way round, he says.

Javier Calleja can boast of a golden decade since his Play Room exhibition at the CAC Malaga in 2008, but the real turning point in his career came last year at Art Basel Hong Kong, thanks to the Nanzuka Gallery.

I work well under pressure and the chance to exhibit in Asia made me want to make a real effort to create something I had always wanted to do, which is these characters, he says.