Abstract: A louvre system is disclosed which includes a frame having spaced apart side frame members (13, 14). A plurality of louvre blades are disposed between, and mounted to the side frame members (13, 14) so as to be rotatable about an axis of rotation. One of the frame members (14) includes a drive arrangement (21) which includes a plurality of gears (28) mounted on a subframe and connected to respective louvre blades. The gears are driven by a timing belt under the drive of a manual or electric actuator, to impart synchronised movement to the louvre blades.