A trial open water swim in the main lake at Stevenage's Fairlands Valley Park has been hailed a success, despite disquiet over water quality and Weil's disease.

Ahead of Love Open Water's event, dozens of people living in Stevenage voiced concerns about the water being stagnant, dirty and potentially contaminated.

One said: "Disgusting idea! The rat population at Fairlands is out of control. Rat urine can potentially contain Weil's disease. If it’s in the water it can be transmitted via ingestion and absorption via cuts."

Weil's disease can cause fever, headaches, sickness and diarrhoea.

Another Stevenage resident said: "I’ve been windsurfing in that lake and the water tastes absolutely disgusting - stagnant and full of goose poo. It’s shallow water with a concrete bottom and you can only see about four inches under the surface. It’s not a nice place to swim."

The organisers, however, say tests carried out prior to the event proved the water quality to be excellent.

A spokesman said: "In the lead up to the session, there were rumours circulating about swimmers being caught in fishing lines, Weil’s disease and poor water quality. All these claims were completely unfounded.

"As a NOWCA - National Open Water Coaching Association - affiliated organisation, we have a responsibility to ensure our venues are safe for the community. A lot of due diligence and planning was undertaken by our teams to maintain the highest levels of safety.

"Water quality tests, taken a few days before the session, showed excellent results.

"Our crew were hand-picked and are highly experienced and qualified open water coaches and lifeguards.

"The local fishing clubs worked with us to make this session a success.

"NOWCA Protect covered swimmers for the session for personal accident and injury, as well as the their commute to the lake."

The £3 trial swim, which had time slots between 7am and 10am on August 29, catered for 60 swimmers of a range of abilities.

The Love Open Water spokesman said: "The feedback has been overwhelmingly positive - so many happy faces on the day and many wanting to come back again.

"We hope to bring more sessions to Stevenage in the future."