The cause of the accident was a misunderstanding between station staff and the driver of a train that was returning to Bicester from London. The station staff thought the train was due to stop at the station. The driver did not.

The station staff had changed the points in anticipation of the train stopping but the driver, not expecting to stop, had not slowed the train down. As the train reached the changed points, its speed and momentum caused the engine to detach from the following carriages, three of the carriages to overturn and the engine to very nearly collide with the stationmaster's house.

Six people died in the tragedy, and 20 more were injured. The death toll could have been much higher, but luckily a doctor and a medical student were on the train and were able to attend to the injured passengers, no doubt saving many lives.

Surprisingly, at the inquest into the accident, it was ruled that the railway company had not been negligent in allowing the accident to take place, although there were a number of recommendations given to help avoid similar accidents in the future, such as requiring all trains to stop at Bicester station in future.