Anglers have been left devastated after an incident in which thousands of fish have been killed in Swindon.

Environment Agency staff were investigating the mass fish deaths at Peatmoor Lagoon today after the alarm was raised at around 7.30am.

Large aerators have been deployed at the West Swindon lake, where hundreds of people fish on a regular basis.

It is not yet known what caused a huge and sudden drop in oxygen levels at the lake.

Peatmoor Angling Club vice-chairman Richard Reeves said members were ‘horrified’ at the discovery.

“It’s devastating. We have lost thousands of fish, of assorted species,” he said.

“It’ll be years of work to replace them.”

Swindon Advertiser: Peatmoor Angling Club vice-chairman Richard Reeves, left, and secretary David RichensPeatmoor Angling Club vice-chairman Richard Reeves, left, and secretary David Richens (Image: Paul Wiltshire)

Mr Reeves, who has been a member of the club for more than 30 years, added: “We’ve never known anything like this.”

Secretary David Richens said they were waiting for the Environment Agency’s verdict on what might have caused the incident.

“At the moment, we just don’t know.”

He said it would cost thousands of pounds to replace the fish.

Oxygen levels in parts of the lake fell to eight per cent this morning, and dead fish could be seen both on the side by an overflow area and in the water.

Bream, pike and perch were among the species affected.

Club member Craig Scragg, from Kingshill, said: “It’s heartbreaking to see. It’s very important for so many hundreds of us who fish here, it’s important for our mental health.

“You just want to know why it’s happened.”

Small groups of anglers from the club and from neighbouring clubs had gathered at the lake this afternoon, along with walkers who enjoy the area.

Lydia Humphries said she had been shocked at what she saw.

“We were stunned when we saw a lot of dead fish, mostly bream. So many dead fish.”

Anglers at the lake were haunted by memories of an incident at the River Ray in Swindon last year, when thousands of fish were killed when a sewage pipe burst.

More than a dozen large tankers parked near the Tawny Owl pub, near the sewage pumping station, after the broken main resulted in sewage leaking into the river.

Environment Agency staff at the scene said they could not comment on the cause of the incident.