CHEMICALS to stop a runway from freezing have leaked into a Lyneham stream causing a grey mould to form on its surface.

Residents reported seeing mould on the Strings watercourse before smelling raw sewage.

Further investigation found a series of problems at RAF Lyneham had caused the problems, including cracked and blocked pipes and incorrect plumbing.

Experts identified the mould as being antifreeze and de-icer from the base's runway.

The Environment Agency says the problems have been solved but the situation is being monitored.

North Wiltshire District councillor Allison Bucknell, who lives in the village, said: "It comes as a bit of a shock that it was polluted but I'm pleased it is being dealt with.

"These sort of things are not usually done on purpose and I believe in learning from mistakes."

Tests, using cameras and dyes, found cracks in water pipes and that plumbing in the mess shower block had been installed incorrectly, spilling waste into the stream.

One pipe had been blocked by fat from the kitchens, forcing raw sewage into the water course.

Bridget Norris, of the Environment Agency, said: "Residents were concerned there was mould and a smell in the water course.

"We have been out to RAF Lyneham and found a few problems, such as cracked pipes and those have been put right.

"There was also an issue that the mould was antifreeze and de-icer from the runway.

"They had a new contractor who had not been told how to get rid of it properly.

"We have pointed out a few things they can improve on.

"We are monitoring the stream and if there are further problems we will make sure it is resolved for once and for all."

A spokesman for RAF Lyneham said the base was working with the Environment Agency to restore the watercourse.