A massive blaze which destroyed a fire station was caused by an electrical fault.

An official investigation into the blaze which tore through Arundel Fire Station last October concludes that either a battery charging unit or an electrical system on a fire engine overheated.

The resulting fire caused hundreds of thousands of pounds worth of damage and meant crews had to operate out of a temporary cabin for months while their building was reconstructed.

There was no smoke alarm in the building at the time as fire stations are not required by law to have them fitted.

However West Sussex Fire and Rescue Service has since installed smoke alarms in its buildings.

A report produced after the investigation and obtained by The Argus said fire crews had experienced problems with a battery charging unit used to recharge electrical equipment on fire engines and ambulances in the days running up to the fire.

The fault had been fixed at least a day before, however when a female ambulance technician arrived at the station for a brief rest period on October 25 she heard a noise coming from the appliance room and quickly noticed the fire.

The report said: "At approximately 1045 hours (the technician) was watching television when she heard a loud "pop" from the direction of the appliance room and became aware of a strong smell of fumes and smoke in the room.

"She turned off the television, picked up her hand-held radio and left the room. As she entered the corridor she looked to her right and saw dark grey smoke coming towards her through the plastic curtains separating the corridor from the appliance room.

"She left the building and used her mobile phone to call 999 to report the fire, she then unplugged her response car and moved it to the roadway."

Despite the battery charging unit having been faulty, investigators are not completely certain that was the cause of the fire.

Further investigations also suggest the possibility that the fire could have started from an electrical fault in the cab of one of the fire engines at the building.

Damaged wiring was found in the cab, suggesting that a device within the vehicle malfunctioned.

The damage caused by the blaze was so severe the report concludes it was not possible to pinpoint the exact location it started.

It said: "It is considered that the fire started accidentally in the area of the appliance crew cab, most likely from an electrical fault.

"For an electrical fault to occur and cause a fire the circuit/apparatus must have been energised.

"It has been identified that a number of circuits are permanently energised, however owing to the severity of the fire it was not possible to establish the precise cause of the fire."

A spokesman for West Sussex Fire and Rescue Service said "lessons have been learned" from the incident.

The report ruled out the possibility of the fire having been started deliberately and concludes it was entirely accidental.