Steering column rotation sensor

A rotational movement sensor arrangement for sensing rotational movement of a steering wheel column 31 within a column housing 29 includes a radiation emitter 2 for emitting radiation and a radiation detector 5 arranged to detect the emitted radiation. The emitter 2 and the detector 5 are mounted on a cradle 33. A disc 24 is mounted for rotation with the column 31, the disc 24 being provided with alternate opaque and transparent portions around a annular path 25. The cradle 33 is slidably mounted on the disc 24 bv means of mating formations 22/23 and 38/39 on the cradle 33 and the disc 24 which are slidable relative to each other in the circumferential direction of the disc 24 so as to retain the cradle 33 in the radial direction relative to the disc 24, with the emitted radiation impinging on the disc 24 at the annular path 25. The arrangement also includes abutments fixed to the steering wheel housing 29 adjacent the cradle 33 to prevent the cradle 33 from rotating with the disc 24.