Heavy rain on Thursday combined with a blockage at the East Calder Waste Water Treatment Works meant plant operator Veolia had to free up capacity by releasing some wastewater into the River Almond.

SEPA says it is investigating the “unauthorised discharge” while anglers and local residents have been voicing their anger and sharing pictures online of wastewater apparently flowing into the river.

The Edinburgh Evening News previously highlighted concerns from the Forth District Salmon Fishery Board (FDSFB) in April following a sewage spillage at the treatment plant.

Alison Baker, clerk to the FDSFB, said: “The Forth District Salmon Fishery Board remains concerned and disappointed that untreated sewage is being discharged into the River Almond. Despite assurances from SEPA and Scottish Water that earlier issues have been investigated and plans in place, it is clear that East Calder WWTW is struggling to deal with the requirements to properly treat sewage from the area.