Homeowners are being warned that badly installed halogen light bulbs could cause a major blaze in their property.

Firefighters are growing increasingly concerned about the popularity of the trendy lights.

More than ever before people are using them instead of traditional bulbs because they last longer and are less intrusive.

But it has been claimed that when poorly fitted, the lights cause a chemical reaction - called pyrolysis - which dries out wood and can start fires.

West Sussex Fire and Rescue Service pointed to a blaze in Aldwick, near Bognor, when halogen lights set a timber joist on fire.

Nigel and Susie Brooks' home in Waters Edge caught fire just after 10pm on Tuesday after thick insulation in the loft, laid by the home's previous owners, caused the bulbs to overheat.

Quick-thinking nephew Samuel Brooks, 39, who was house-sitting, managed to raise the alarm after smelling burning.

His actions have been praised by Mr Brooks who believes the damage could have been far worse.

Mr Brooks, who only moved into the property in July, said: "He went up into the loft, which was thick with smoke. He acted very quickly.

"The fire crews were amazed that the fire was not worse than it was."

Crews managed to bring the blaze under control by 11pm and Mr Brooks escaped unharmed. However thousands of pounds worth of damage was caused by the blaze.

Firefighter and head of community safety for West Sussex Fire and Rescue Service, Roger Wood, said: "Please make sure your halogen downlighters are fitted with fire resistant hoods or that there is a sufficient gap between the lights and roof insulation or roof timbers.

"Halogen downlighters do get extremely hot and they will set fire to insulation or timber if they are installed too close.

"If a fire does start to smoulder it is likely to be in an area that doesn't have smoke detectors, like roof spaces or ceiling voids. This means the fire could develop without you knowing until it is too late."

A Fire and Rescue Service spokesman added: "On their own halogen bulbs are fine. Most people have them these days. But when they are fitted incorrectly or poorly they do pose a danger.

"And because of the unexpected nature of the fire, it can take people unaware. Most people don't realise how serious a problem it can be."

A spokesman for DIY giants B&Q said: "We would always urge people to fit all products correctly and safely.

"Lighting can be particularly dangerous if fitted not in accordance with the guidelines."

have you experienced a fire due to poorly fitted halogen light bulbs? Tell us your stories below.

Pyrolysis fact file.

Pyrolysis is a form of incineration that chemically decomposes organic materials by heat in the absence of oxygen.

It typically occurs under pressure and at operating temperatures above 430C or 800F.

The process requires a drying of whatever material is affected prior to the reaction occurring.

Pyrolysis is often used to treat industrial materials such as fuels and pesticides.

Halogen lightbulb factfile.

Halogen bulbs use a tungsten filament and operate at a higher temperature to traditional lightbulbs.

Because the bulbs must be very hot, the halogen bulb's lens must be made of hard glass or fused quartz, instead of ordinary soft glass which would soften.

The design of halogen lights typically allows them to last longer and burn brighter than most other bulbs.