The A37 speed camera has been repeatedly vandalised

They say a two-foot high blue box has appeared on the A37 near Shepton Mallet, by the Gatso speed camera.

Brian Upshall, who runs Fosseway Garage opposite, said: "It's very secretive. You wonder what they'll do next."

The Avon and Somerset Safety Camera Partnership refused to confirm whether a covert camera had been installed.

A spokesman said it was supporting police to track down those who had attacked the cameras.

Camera 'eye'

He said: "All such cameras in our area are so located as a result of casualties.

"We are using any available system that we can, which includes cameras, observations, and the support of our communities to support our casualty reduction programme."

Local people say they have also noticed a 50mph speed limit sign facing the camera is unusually thick and a tiny "eye" can be seen in the back.

A spokesman for the Association of British Drivers said: "While speed cameras often have a notice saying they are connected to a central alarm system, it is the first time I've heard of something like this."