The collision was the result of a signal failure caused by a wiring fault. New wiring had been installed, but the old wiring had been left in place and not adequately secured. An independent inquiry chaired by Anthony Hidden, QC found that the signalling technician responsible had not been told that his working practices were wrong, and his work had not been inspected by an independent person. He had also performed the work during his 13th consecutive seven-day workweek. Hidden was critical of the health and safety culture within British Rail at the time, and his recommendations included ensuring that work was independently inspected and that a senior project manager be made responsible for all aspects of any major, safety-critical project such as re-signalling work.