A wild swimmer, diminutive against a brooding mountainside, a fell farmer bottle-feeding a calf, memory traces of mine tracks and old stone walls through moor and mire… The large canvases of Julian Cooper that comprise this Lines of Descent exhibition are both visually arresting and psychologically unsettling. The Lake District’s pre-eminent painter, Cooper challenges our perceptions of Britain’s uplands, a landscape contingent on forces of not only raw nature but those of economics and public prejudices