Alarm over river pollution was raised after garage workers appeared to be fly-tipping near River Chess.

A resident took to the social media platform Twitter after spotting three men in hi-viz working on the side of BP Londis garage in Chesham on Sunday April 16.

The men appeared to be throwing building waste into the waterway as they put up a new fence on the edge of the garage on Amersham Road. 

The Tweet by the concerned resident sparked hundreds of comments and reactions, including a retweet by the The Understones lead singer Feargal Sharkey.

Although not part of River Chess, the watercress bed is closely linked to the precious chalk stream habitat.

River Chess Association’s chair Paul Jennings said: “It’s not actually the river, but they are connected and water will drain into the river, so if there’s anything toxic being thrown in it will end up in the river.

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“There was a while back a load of litter being dropped onto the footpath behind the site so they don’t have a very good track record.”

He told anyone treating River Chess as a tip to “treat all water courses with respect.”

“If you dump into a river it flows away from where you are and it’s no longer a problem for your it is for someone else,” he added.

The waterway next to the garage was once used to farm watercress, a major industry in Chesham in the Victorian times supplying London via the Metropolitan Railway.

Buckinghamshire Council’s deputy leader and cabinet member for climate and environment Gareth Williams commented the fly-tipping: “Buckinghamshire Council is investigating this incident and has consulted the Environment Agency as a courtesy, as part of our usual procedures for this type of incident.

"Consideration will need to be given as to whether offences have been committed under the Environmental Protection Act 1990. Potential environmental impacts will be assessed during this process. We will fully investigate and examine the evidence available to determine what action can be taken against any offender.”

Mr Jennings was at River Chess conducting a fish survey when he spoke to Bucks Free Press, saying the samples were “turning up quite positive” thanks to good flow recently.

In early February, River Chess Association volunteers spotted ‘unusual’ foam discharge in River Chess beyond  the Chesham Sewage Treatment Works.

The pollution scare prompted an investigation by Thames Water to trace the source, including speaking with local businesses to try to identify the substance.

Mr Jennings feared at the time the chemical was a result of fly-tipping by an unlicenced trader.

He said: “It wasn’t toxic and certainly from all the surveys we did it wasn’t anything detrimental. The view was it shouldn’t be in the river and it hasn’t gone through the process but it is concerning. It brings to mind that the sewage works can’t treat everything.”

BP, Londis and the Environment Agency were contacted for a comment.