Spearheaded by Artangel, ‘Afterness’ is a group exhibition scattered across Orford Ness, a spit reachable only by ferry on the Suffolk coast. Nowadays under the care of the National Trust, Orford Ness has had a secretive history for much of the 20th century, having served as the base for experiments into radar, bombs, and atomic weaponry. Local folklore of mermen, and UFO sightings in nearby Rendelsham Forest, further augments Orford Ness’ idiosyncratic character. Yet Orford Ness’ distinctive history, plus the sense that this is a landscape on the cusp of eroding into the North Sea, inevitably poses a test or challenge for any artwork to be exhibited here. On balance, ‘Afterness’ just about meets that challenge and makes for a fascinating, though fascinatingly problematic, exhibition.