A meltdown of Britain’s train scheduling system that caused chaos for travelers over the summer months was caused by a lack of government and rail industry leadership, according to an official inquiry.

The Department for Transport, system manager Network Rail Ltd. and the operators of England’s Thameslink and Northern rail franchises “all made mistakes which contributed to the collapse of services,” the Office of Rail and Road said after publishing the report Thursday. The ORR itself was also found to have been at fault.

Swathes of Britain’s rail network were thrown into turmoil following the introduction on May 20 of the biggest timetable change in a generation. The industry “placed engineering and planning concerns ahead of serving its passengers” the study found, while Network Rail and the DfT didn’t fully understand the risk of major disruption.

Transport Secretary Chris Grayling separately announced a review of the U.K. rail industry which could go so far as to consider renationalization.