A tactile sensor includes a first layer formed of flexible material having an outer contact surface and an opposed inner interface surface, a second layer formed of substantially transparent flexible material arranged in substantially continuous contact with the flexible first layer at the interface surface, a camera, and reflective material. The first and second layers are configured so that pressure exerted by an object or objects contacting the outer contact surface causes at least localized distortion of the interface surface. The camera is arranged to capture an image of the interface surface through the flexible second layer. The reflective material is configured so that the appearance of at least part of the reflective material changes as the viewing angle changes and the reflective material is located between the layers at the interface surface.