A fire was started in a bedroom of a retirement home due to sunlight reflecting off a mirror or a magnifying glass.

The incident happened yesterday at a retirement home in Cauldon Avenue, Swanage.

Dorset & Wiltshire Fire and Rescue Service was called to the property at 9.46am, with five fire crews attending from Swanage (two), Poole (two) and Wareham, supported by the aerial appliance from Westbourne. Six breathing apparatus wearers, two hose reel jets and a safety jet were used to tackle the blaze.

All of the home’s residents were quickly brought to safety, with four being assisted by firefighters. The fire damage was contained to the one bedroom, thanks to the building’s fire doors working effectively.

Group Manager Richard Coleman said: “The fire started in a bedroom and the investigator concluded that the most likely cause was sunlight reflecting off a mirror or magnifying glass, as both were by the window. Where you have a mirror or any other glass object that is curved, this allows the glass to act as a lens. When the sunlight hits it, it becomes concentrated and, if the rays are bounced onto something flammable – in this case, curtains - then a fire can start.”

He added: “The likelihood of this happening 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 by a window.”

Mr Coleman praised the multi-agency response to the incident, which saw paramedics from South Western Ambulance Service, officers from Dorset Police and staff from the home working together to help the affected residents.

He said: “There was an ordered evacuation of the premises, good care of the residents once outside, and a methodical search of the building by firefighters in support of the staff’s roll call to ensure that everyone was safe. The Sandbanks ferry emergency procedures helped us to get all necessary resources to the scene in a timely manner, so our thanks go to them.”