An order issued to governors last year outlines a supposedly fail-safe system to deal with cases that had slipped through the net.

However, the drone has an automatic fail-safe system that takes control in emergencies.

Engineers manually overrode the ride's automatic fail-safe system, before instituting the restart procedure, which sent the loaded train down the track.

There are no fail-safe systems on hand to suggest that the shift into second will over-rev the engine.

On any river, but on this river above all, fail-safe systems should have been in place that would have overridden or alleviated carelessness or chance.