Lincolnshire fuel tank maker Tanks R US has developed a diesel tank monitoring system called Tank Eye.
Based on the GuardCam sensor/light unit, it combines a motion sensor, floodlight and digital video camera. It also shouts out an audio warning to potential thieves, using either a standard built-in warning or your own recording.
The firm has also added a radio-based function, which gives a remote alarm that operates over a distance of 70-80m. Cost is £149+VAT.