The chairman of a country park that suffered a “worrying setback” following a series of sewage spills from a treatment centre owned by one of the country’s biggest water supplier’s has welcomed a £1.5 million commitment for environmental improvements.

Hundreds of fish and birds died over a two-year period when "out of control" sewage treatment centres, owned by Thames Water, sent untreated water into rivers in Buckinghamshire and Oxfordshire.

The sewage spills from Little Marlow Sewage Treatment Works (STW) “seriously affected” a large part of the 330 hectare Little Marlow Country Park, causing problems for the walkers, joggers, birdwatchers and anglers who used it.

With large quantities of untreated sewage released into the Thames, a riverside meadow adjacent to the treatment works was “badly polluted” along with a several footpaths and the Spade Oak Brook, where dead Pike were found.

The pollution also made its way into Spade Oak Lake, a central feature of Spade Oak Nature Reserve.

The long-term impact on the lake’s fishery is still unknown.

Last month, Thames Water was ordered to pay more than £20 million in fines and costs for the pollution incidents at Little Marlow and five other sites.

Following sentencing, Thames Water also announced it would allocate £1.5 million towards projects to improve the rivers, wildlife and surrounding environment at the six locations.

Mike Overall, chairman of the Country Park Community Partnership welcomed the move and said the “unhappy period” needs to be put behind them.

He said: “As the largest recreational area of natural environment in the immediate area of the six sites affected by pollution, the Little Marklow Lakes Country Park should benefit from this additional funding for environmental projects.

“Over the last 18 months we have left Thames Water and the Environment Agency in no doubt about the seriousness of these pollution incidents on the development of the country park.

“The country park and the Little Marlow STW have to co-exist. We must now put this unhappy period behind us and concentrate on the development of the country park.

“Such process failure incidents cannot be allowed to happen again. If they do, any spills must be contained within the STW site.”