The government's conservation adviser warns the county council shouldn't give the 'energy from waste' plant planning permission unless it can be certain it will not have an adverse effect on The Wash and Roydon Common.

In its response to consultation over the incinerator planning application, Natural England says the figures do not stack up, when it comes to claims over the impacts that the plant will have on the environment.

'From the information provided, it is Natural England's view that this proposal is likely to have a significant effect on the European site due to potential impacts on invertebrate populations, in particular shellfish beds,' it states in an e-mail to Norfolk County Council.

It also fears that the incinerator would have 'a significant effect' on Roydon Common, an internationally-important nature reserve near King's Lynn.

Natural England says environmental assessments included with the planning application do not include enough information.

It says where The Wash is concerned, the risk of long-term build up of pollutants from the incinerator and their cumulative effect on the shellfish beds should be considered.

'Having worked through the information in the ES [environmental statement], we do not agree with the assessment made in the ES of no likely significant effect,' its letter adds.

'We note the standards used in the report are the American Government's Environmental Agency's Human Health Risk Assessment Protocol.

'In England the regulatory authority for the control of emissions is the Environment Agency.'

Norfolk County Council today declined to discuss the response from Natural England in detail. But a spokesman said: 'It's almost certain that there will be further information needed from the applicant.'

A spokesman for Cory said: 'The Consortium will be liaising closely with Norfolk County Council's planning department and will be reviewing all responses received to the planning application.

'We will respond to all issues raised in accordance with the due planning application process. We will not be commenting through the media on individual responses.'

Anti-incinerator campaigner Mike Knights said: 'I am delighted Natural England recognise the threat posed by the incinerator.

'Norfolk County Council have previously tried to dismiss opponents as if we do not understand the technology. In fact we have a very good idea what would be discharged and what the impacts would be.'

Responses received during the consultation appear almost unanimously opposed to the incinerator, which Anglo US consortium Cory Wheelabrator wants to build at Saddlebow, south of the A47.

Town and parish councils across Norfolk have come out against the incinerator, with 53 opposed, 10 in favour and 16 neutral according to the latest responses published on the county council's website.

Opponents say this means the county council will not be able to show the 'broad consensus' needed to qualify for the �169m of PFI (Private Finance Initiative) credits needed to build it.

One of the latest replies to be published comes from the parish council at Roydon, near King's Lynn.

It highlights concerns about the common, which is home to rare species including raft spiders, natterjack toads and grey shrike.

Follow the links above for all the background and to read all the responses on Norfolk County Council's website.