“Finding huge amounts, huge numbers of fibres in that flowing river – it’s worrying – it’s absolutely worrying,” said Dr Corina Ciocan, principal lecturer in ecotoxicology at the University of Brighton, where the samples are sent.

“It points towards a constant contamination. It’s a chronic contamination that is ongoing every single day.”

Strands of fibreglass have also been detected in the samples sent to Dr Ciocan’s laboratory.

“I’m used to finding those particles in estuaries and in the ocean. I point the finger towards poor boatyard practices or abandoned boats,” she explained.

“In a chalk river that’s a little bit scary and a little bit of an unknown. We need to dig a little bit and see where those are coming from.”