At a time when other museums are building new wings, we are building a new image; our extension will be through programming in concentric circles: the Serpentine, the park, the world. The gallery offers a very specific experience, because it’s a world within a world – a lofty space, which you walk to through the park. The change of momentum from slow to fast, and from noisy to as silent as a chapel is important; it works especially well for monographic exhibitions.’