A simple idea by two Gatwick technicians is cutting pollution and saving money.

The idea for storing and treating contaminated water from the airport's runway came from John Monk and John Barber.

It cost BAA, the airport's owner, £1,000 but saved £14,000 on a scheme proposed by a firm of consultants.

Long periods of heavy rain and cold weather had filled the airport's balancing pond -which collects rainwater from the runway - and storage lagoon, which collects dirty water.

Following one of the wettest winters on record, the lagoon had almost reached capacity and low temperatures meant large amounts of de-icer were channelled into it.

Had the lagoon reached capacity, it would have resulted in local flooding by the contaminated water.

A survey found overspill water from the lagoon was contaminating clean water, leading to unnecessary treatment costs.

A plan by the engineering consultants proposed major changes to the pond at a cost of more than £15,000.

Before that option was pursued, the two technicians came up with their own solution which would achieve the same result at a fraction of the cost.

The scheme prevents overflowing and keeps clean water away from dirty water.

An automatic sampling system determines the level of pollution in the water.

Clean water is aerated and discharged into the River Mole, while the dirty water is diverted to the storage lagoon and fed into Crawley's sewage system.

Paul Boynton, Gatwick's general manager, said: "It is often the simplest ideas that are the best and this is a classic example.

"Both Johns spent a lot of time and effort on this project which was actually outside their usual duties.

"They demonstrated an exceptional level of skill and ingenuity and, in doing so, have saved a significant amount of money."

BAA Gatwick's new managing director, Roger Cato, who has a background in engineering, was keen to pay the two men a visit.

He said: "I am really impressed. The guys have done a tremendous job.

"It is a great example of thinking outside the box.

"We welcome ideas from our employees which can help our business, especially those which save us money."