<p>A pipeline inspection vehicle comprises a main body (10) driven through a pipeline by fluid flow against resilient cups (12). Resilient fingers (20) carry a circumferential array of magnetic proximity sensors for sensing the spacing between each sensor and the metal of the pipeline wall. Wheels (18) biased into engagement with the pipeline wall provide one form of distance measurement. The vehicle has on-board data storage by way of a memory housed within a pressure vessel.</p>
