The environment agency has been criticised for failing to act swiftly after a river on the outskirts of a west Suffolk village allegedly became polluted by sewage.

The agency was contacted on Saturday after concerned Lavenham residents discovered hundreds of dead fish in the river Brett, which runs along Lower Road.

Lavenham parish council also called the agency to report the fish deaths.

Keith Webb, who lives alongside the river, was the first to report that the water had “turned brown and stank of sewage”.

Environment officers did visit the site, but not until around 16 hours after the call, and according to Mr Webb, they failed to investigate the source of the pollution.

He told the EADT: “It was on Saturday around 4pm that I noticed the dead fish and the awful smell so I rang the environment agency and they said they would send someone out straight away.

“In the meantime, I took samples from various points along the river finishing at the Bury Road and traced the source to the point where there was a septic tank being emptied by pump into the stream. There were dead fish all along a one-and-a-half mile stretch.

“I called the agency again at 9pm and warned them that hundreds of fish were going to die but I was then told they couldn’t come out in the dark because of health and safety.”

The following morning an environmental officer eventually arrived and tested the samples Mr Webb had extracted from the stream.

He continued: “The samples went bright orange which denotes ammonia in the water. I told the officers where the pollution was coming from and they said they would investigate, but they didn’t and so no action was taken.

“They have a 24-hour hotline and I think it’s a disgrace that they didn’t send someone out immediately on the Saturday so they could have done something while it was happening.”

Lavenham parish clerk Jane Bellward confirmed the parish council had received calls from people about the dead fish in the Brett and that she had also contacted the environment agency to register the complaints.

Last night, an environment agency spokeswoman confirmed that officers had not been able to visit the site until the Sunday, by which time the ‘pollution’ had dissipated. She said Mr Webb’s samples could not be used as evidence because the containers were not sterile.

She added: “Following a report of dead fish and odour coming from the River Brett in Lavenham, we visited the site twice (on the Sunday).

“Whilst there were a handful of small dead fish, our sampling on both occasions was normal.

“While dead fish are understandably a cause for concern, sometimes it can be a natural occurrence.

“At this time of year, daily changes to water temperature along with reproductive stress can cause fish deaths.”

If anyone has any concerns about pollution the agency encourages them to call a 24-hour incident hotline on 0800 80 70 60.