The inquiry was chaired by QC Anthony Hidden and published a report in September 1989. It found that the direct cause of the disaster was sloppy work practices in which an old wire, incorrectly left in place after rewiring work and still connected at the supply end, created a false feed to a signal relay, thereby causing its signal to show green when it should have shown red. A contributing technical factor was the lack of double switching in the signal relay circuits, which would have prevented a single false feed causing an accident.