Last month, a steady stream of them turned up to the opening of the £500,000 extension to the Lisson Gallery in London, expecting canapes and cocktails. Imagine their frustration at being confronted by a sheet of corrugated iron across the entrance. "It was as though they were saying: 'Just get me inside and give me a drink. That's what I've come for.'" So the invitees weren't so much frustrated at being deprived of an aesthetic experience, but angry because they couldn't get inside for champagne and nibbles? "Obviously," says Sierra. "I mean, there were 10 other openings in town that night. And the aesthetic experience was right in front of them. The corrugated sheet was beautifully made. They just weren't ready to look at it."
Now that's what art is about, I think; more so than pretty landscapes, portraits of sportsmen and prime ministers and safe, bourgeois decorative objects. More in the realm of conceptual terrorism.