Hughes's term of office was also deeply affected by the tragedy at Aberfan in October 1966, when a colliery spoil heap engulfed the primary school, leaving 144 dead, the vast majority of them children. Hughes immediately flew to the scene, and helped direct the rescue effort and ensure the well-being of survivors. An inquiry was set up under Lord Justice Edmund-Davies which, amongst its conclusions, stated that Lord Robens, the National Coal Board chairman, had misled Hughes in claiming that all tips were regularly inspected. Hughes described the Aberfan disaster as the darkest days of his life.