The testing kit costs around �650

Roger Waldron from The Science Shop in Wolverhampton says the deaths from the latest outbreak of the disease pushed him to put the kit together.

Two women from Redditch died earlier this month from the disease.

On Friday officials in the two counties said the source of that outbreak may never be traced.

David Kirrage, director of the Health Protection Agency in Herefordshire and Worcestershire, said half the samples taken had been examined and no source isolated.

'Reworking existing equipment'

The testing kit, which costs around �650, consists of two electronic test instruments which will show when conditions are right for the proliferation of the Legionella bacteria.

Roger Waldron said: "Myself and other colleagues were playing around with the idea for the last few months, but we were prompted into action by your report on Legionnella cases in Redditch", he told BBC News Online.

"You had a direct influence on us so it was only a matter of months that took this to come into force.

"The equipment is not new or revolutionary, we are just reworking existing equipment.

"The advantage of the test kit is in its cost effectiveness, enabling building managers and employers to take control of the situation by implementing an effective monitoring programme."

Breeding the bug

So how does the kit work? It consists of two electronic metres, buffer solutions and a probe to take a water sample.

The solution is added to the sample which will show a slight colour change. A reading will indicate if the environment is right for the bug to breed in.

Large buildings, hotels, hospitals, spa baths, caravan sites - any company with a hot water system - could benefit from use of the kit, Mr Waldron said.