An Australian company, Phoslock Water Solutions, contacted Petersfield Town Council's Heath Pond working party and said adding modified clay to the water could rid it of phosphorus.

However, the working party remain unsure whether modified clay, or plans to introduce predators into the water to alter the eco-system, would stop the problem long-term.

The working party is now considering other potential solutions. Town clerk Neil Hitch said the Environment Agency had reservations about whether Phoslock's method would work at the pond.

He said: "They have got questions about Phoslock – they are not totally convinced it is a sustainable solution to the problem." They are also not convinced that action such as biomanipulation does work.

"I am not convinced it is going to work either."

Mr Hitch added: "I was always very clear at the start of this process that we should not jump into bed with the first person that provides us with a solution."

He told the working party that a UK company called Spirex Aquatec was interested in solving the problem. It specialises in making pond aerators, which increase the oxygen content of the water and help fish to survive.

Mr Hitch said: "I have heard from a gentleman called Dr Andrew Worthington, who called me out of the blue.

"They also offer a potential solution to the problem we have here.

"In my discussion with Dr Worthington I mentioned aerators which was considered to be irrelevant by Phoslock, but he thought it could be part of a viable and sustainable solution.

"I have got a note of his web address but I have not had a chance to look at it in any sort of detail."

Petersfield Angling Club secretary Bryan Worwood said: "Dr Worthington is from a company called Spirex Aquatec.

"They are based in Redditch (Worcestershire) and they have got quite a big website for pond healing remedies.

"They are all various organic solutions and they talk about exactly the things we have been suffering."

He added: "I think we should get them to come to us to get a sample and give us a presentation.

"Phoslock was impressive when they did their presentation but they are salesmen.

"They have got to be biased to their own product."

Mr Worwood said other options worth pursuing included contacting Sparsholt College to see if it could offer any assistance, and asking for advice from leading universities.

Work on the Norfolk Broads could also give clues on solving the problem, after mud-pumping to remove nutrients there successfully restored lake water.