Sir, RWE npower is being more than a little disingenuous in suggesting that "Lake H/I", one of its ash dumps at Radley, is part of a purposefully designed flood management system. Nothing could be further from the truth.

The one-way flap valves in the perimeter of this structure are nothing more than an afterthought to give the appearance of mitigating the flood risk presented by this massive imposition on the Thames floodplain.

They are supposed to allow the river to flood across the lake' surface. In January 2003, these valves failed to operate, because of overfilling. In July, the valves did allow some water to flow in, but, due to ash in the lake, only about half of the surface was available, with a result that less water entered than should have.

Even with everything working properly, there is no way that this 17-hectare intrusion upon the floodplain is an improvement upon the real lakes that it replaced.

This time, Abingdon escaped being flooded from the Thames by a whisker. Additional flood mitigation is clearly required. The 14 hectares of Bullfield and Thrupp Lakes remain available, and could be incorporated into a properly designed flood protection scheme, but only if npower leaves them be. Otherwise a 12-hectare lake will be turned into a 12-hectare mound of impermeable ash and clay, which will shed water faster than a duck's back.

npower's suggestion that the proposed new drainage ditch will usefully store floodwater, is ridiculous. The amounts are much too small to matter. What the ditch will do is carry water more efficiently to the Thames, and potentially add to flooding problems.

npower's published statements on this topic are not only further examples of their callous disregard for local public opinion, but also an insult to people's intelligence.

Dr Basil Crowley Chairman Save Radley Lakes