A rotary actuator (10) has a driven element (20) comprising a plurality of recesses (30) that are spaced in a circumferential arrangement around an axis of rotation (22) of the driven element (20) by a spacing angle (32), and first, second and third latch elements (40, 60 70) that are each movable between a retracted position (42), and an extended position (44) in which it is engageable with a corresponding one of the recesses (30). Sequential movement of the first, second and third latch elements (40, 60 70) between retracted and extended positions causes rotation of the driven element (20).