SUNLIGHT reflecting off a mirror caused a fire that badly damaged the bedroom of a house at Charlton, investigators believe.

Crews from Malmesbury, Tetbury, Cricklade and Chippenham fought the blaze in Park Street on Saturday afternoon with the help of firefighters from Cirencester.

The quick-thinking occupant closed the bedroom door and the fire was contained.

Ian Jeary, from Wiltshire Fire Service said mirrors and glass objects with curved surfaces acted as a lens.

“When the sunlight hits it, it becomes concentrated, and if the rays are bounced onto something flammable, such as curtains in this incident, then a fire can start.”

He explained: “The principle is the same as using a magnifying glass to start a fire. It does depend on the angle of the sun, but any mirror or glass ornament with a curve in it should never be left on a windowsill or surface by a window.”

He added that damage to the house in Charlton was kept to a minimum because the occupiers were at home and the smoke detectors sounded, raising the alarm.