The Brett Ashford Triathlon due to take place on Sunday week has been cancelled following the closure of Conningbrook Lake.

The Country Park facility next to race headquarters at the Julie Rose Stadium – used for the swimming discipline – has been closed down by the Environment Agency, due to the return of a blue-green algae, hitting the race for the second successive year.

Twelve months ago, toxicity levels more than 10 times the limit mean't the first section of the standard and sprint events had to be replaced by a 2.5k run.

Explaining the decision to call off this year's event, race director Liz King from organisers Tri Spirit Events said: “We are disappointed and it’s gutting but we wanted to do the right thing by our competitors.

“We feel the only reasonable thing to do is offer them the option to transfer to a different event or get a refund.

“The Environment Agency says that two weeks of clear testing needs to happen before the lake is all right to swim in - we are now out of time, especially if we are to give people sufficient notice to change their plans.

“This has had a big impact on our business and we are disappointed. We have spent years working hard to build our reputation and the ongoing problems are taking their toll."

She added: “We take advice and guidance from the two governing bodies British Triathlon and Triathlon England, EA, Ashford Borough Council and Ashford Leisure Trust. We do not want to put athletes at risk.

Meanwhile Tri Spirit’s Owler Marathon on Sunday, July 23, has received national recognition and will double as the Tri England National Middle Distance Triathlon Championships, believed to be the first time they have been staged in the South East.

King said: “It’s a big year for us - great for Ashford, and puts us on the map as a triathlon venue

"However, the algae is a real concern and we are already working on a back-up plan.

“A blue-ribbon event is hard won,and we are grateful to Brett Group – who have supported us from the beginning – and Mid Kent Fisheries and we are working with them to secure an alternative lake in case if we need it."