Environment campaigners have claimed Dorset's draft local plan proposals for 39,000 new homes in the county over the next 17 years should be halved.

The Dorset Climate Action Network says the current Dorset target is flawed and could not be achieved without damage to Areas of Outstanding Natural Beauty and greenfield sites and would impede the council's own climate strategy to cut greenhouse gas emissions. They also say it would be against government planning policy to protect the best green spaces.

Professor Michael Dower and the Dorset Climate Action Network claim in a letter to Dorset Council that the planning portfolio holder Cllr David Walsh is wrong when he suggests Government housing targets have to be followed and that the county needs to also allow for 9,000 extra homes which Bournemouth and Poole is unable to accommodate.

"The only way that sites for more than about 20,000 houses can be found is by making large encroachment on the AONB, breaching the Green Belt and using large areas of greenfield land, all of which are against government policy.

"The Sustainability Assessment in the local plan shows that almost all new sites proposed for housing or workspace would, if developed, cause grave damage to landscape and to biodiversity and would gravely impede the council's own Climate Strategy to cut greenhouse gas emissions," said the preamble in a question to the Dorset Council Cabinet.

The statement argues that Dorset need not follow the Government standard methodology in assessing housing numbers and can use a different method if 'exceptional circumstances' apply. This could include the large proportion of Dorset which is listed as Area of Outstanding Natural Beauty together with sites such as rare heathland the Jurassic Coast.

The campaingners say that there is no obligation to meet need for housing from neighbouring authorities and points out that no request to take extra housing has been made by the Bournemouth, Christchurch and Poole council.

"In view of these points, will the council think again, cut its new homes target from 39,000 to 20,000, and save the county from the impact of a serious and unnecessary over-estimate of housing need?" said the question.

But Cllr Walsh rejects the arguments and says Dorset Council cannot only plan for local need and does not believe there are exceptional circumstances to justify avoiding the Government standard calculation.

"Whether that need (including any unmet need from neighbouring areas) can be met within the environmental constraints of the plan area is a different matter, which will be considered carefully," he said in a response to the question.

He says that although the BCP council has not yet quantified how many homes it may need Dorset to help with it has said that its area has "a significant and challenging housing requirement" which the area will be unable to meet.