The results of samples taken from the River Usk at Llanfoist Bridge have returned no evidence of any pollution in the water after locals and campaigners expressed their worry at the site of a discolouration in the water.

A former river warden and fisherman made the discovery on Sunday evening while out walking and raised the alarm bell to Natural Resources Wales (NRW). The watchdog instructed Dwr Cymru Welsh Water to carry out tests at the site and take samples for analysis. These show no signs of pollution, but they say that checking the nature of the ‘brown scum’ was the right thing to do.

“We received a report of suspected pollution in the River Usk near Llanfoist Bridge, Abergavenny, on Sunday July 12,” a spokesperson for NRW said.

“Following an initial assessment, Dŵr Cymru Welsh Water attended the location at our request and carried out an investigation.”

"The investigation found no evidence of sewage pollution or any issues with nearby wastewater assets. Based on the findings of the investigation, we believe the brown foam and water discolouration were caused by algae affected by the recent hot weather, rather than by a pollution incident. We will attend the site to verify these findings.”

“Suspected pollution should be reported to us immediately online at naturalresources.wales/reportit or through our incident hotline on 0300 065 3000.”

The photographs were also sent to the Save the River Usk Foundation, who are reportedly running their own, independent analysis. Whether their findings concur with the result from the water supplier is yet to be seen.

In a statement, Dwr Cymru Welsh Water confirmed they had been asked to send specialists to the river. The organisation confirmed their local infrastructure is running well.

“Following a report of pollution from NRW we attended the River Usk in Abergavenny on Sunday to investigate,” a spokesperson said.

“Our storm overflows in that area have not spilled for weeks and all our assets there are operating as they should.”