A novel form of rotary pneumatic actuator, incorporating flexible, inflatable elements, has been investigated with a view to its use in closed loop position control applications. The characteristics of the patented actuator (registered trade name ‘Flexator’) have been analysed and a model predicting static torque produced, which is consistent with experimentally-derived data. Hysteresis is a significant feature of the characteristic and suggestions are made as to how this effect can be minimized. Modifications that allow the production of constant torque over full stroke, which can be a maximum of just under 360°, are also described. A PC-based digital controller, based on techniques already in use for more conventional pneumatic actuators, has been implemented on a one degree of freedom test rig. The dynamic performance achieved with steady state errors of ± 0.2° indicate it would be feasible to satisfy the specifications for a horticultural robotic manipulator using flexible rotary actuators.