The protestors are trying to save their "natural nature reserve"

The development, by Prudential, aims to turn former gravel pits east of Theale into a new town for 16,000 people.

Large parts of the Kennet valley super estate would be built on a flood plain.

About 60 residents, councillors and MP for Reading West, Martin Salter, held a demonstration beside the River Kennet at Burghfield on Saturday afternoon.

They fear building on the flood plain could result in flooding in central Reading as well as the loss of "a natural nature reserve".

Campaigners want the government to reject the South East Plan panel's recommendation that the Kennet Valley Park development should go ahead.

'Seriously flawed'

Mr Salter said: "The panel's recommendations are seriously flawed and take no account of the increased flood risk that would be caused by building on the functional flood plain.

"I am urging everyone who cares about the future of south west Reading to sign up to our campaign so that I can present the most powerful case possible to planning ministers to protect the Kennet flood plain."

Chris Giles, local resident and campaigner, said: "The area the Prudential have purchased is a natural flood plain with disused gravel pits that local fishermen, the sailing club and water ski club currently enjoy.

"It also serves as a natural nature reserve, which has an abundance of wildlife and is one of the top sites for nightingales."

The Environment Agency has also expressed concerns about the consequences of building on a flood plain and the development of a natural beauty spot.

Prudential has said it is planning to resubmit a revised plan for the Kennet Valley park development, which takes into account the flood plain issue, in "early summer".