A Needham Market mum was horrified to discover her children had been swimming neck-deep in a river where hundreds of dead fish were rotting upstream.

Mother-of-two Suzanne Mildinhall, 40, regularly visits natural swimming spots in Suffolk with her four-year-old and nine-year-old children.

East Anglian Daily Times: Mother-of-two Suzanne Mildinhall, 40, regularly visits natural swimming spots in Suffolk with her four-year-old and nine-year-old children.Mother-of-two Suzanne Mildinhall, 40, regularly visits natural swimming spots in Suffolk with her four-year-old and nine-year-old children. (Image: Suzanne Mildinhall)

However, after letting them swim in neck-deep water in the Hawks Mill area of Needham Market, Mrs Mildinhall was horrified to be told of the "putrified mess" just upstream of their location.

"After 20 minutes of paddling, a local resident rushed to warn us that the River Gipping was contaminated," she said.

"I immediately got the children out of the water and put them on towels in the car.

"When we got home, I power showered them off. It's just disgusting."

East Anglian Daily Times: Hundreds of dead fish have been spotted in the river.Hundreds of dead fish have been spotted in the river. (Image: Zoe Alexander)

Mrs Mildinhall worried she had missed a sign, but the resident told her they had been in touch with the Environment Agency to no avail.

"My children were paddling and splashing, so I was worried they would get sick," added Mrs Mildinhall.

"We love wild swimming in natural spots rather than chlorinated pools, but you could be swimming in all sorts."

The River Gipping Trust's restoration manager Ian Petchey confirmed that he had noticed the dead fish on Wednesday, August 16 while completing footpath maintenance nearby.

East Anglian Daily Times: The Environment Agency has taken water samples from the river.The Environment Agency has taken water samples from the river. (Image: Zoe Alexander)

Mr Petchey reported the issue to the Environment Agency who took water samples to find out the cause.

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A spokesman for the Environment Agency said: "We are investigating reports of dead fish in the River Gipping at Needham Market.

"No signs of pollution have been found at this stage.

East Anglian Daily Times: The cause of the deaths is currently unknown.The cause of the deaths is currently unknown. (Image: Zoe Alexander)

"Members of the public who spot fish in distress should report it to our 24/7 incident hotline: 0800 80 70 60."

The Environment Agency also confirmed that it is the responsibility of the landowner to put signs up in the area should they consider it necessary.