A louvre shutter comprising louvres 20 rotatably mounted in a frame on louvre axles, and a louvre drive system that, in summary, comprises a rack and pinion gear system including an externally operable rack assembly and a set of pinion gears 28 mounted to the louvre axles. The rack is externally operable rack and is reciprocably mounted in the drive system housing 42, 48. The pinion gears 28 mounted to the louvre axles are engaged with the rack such that reciprocation of the rack rotates the louvre 20 relative to the frame.