Mr Dimbleby said the development would be vandalism
Veteran broadcaster and journalist David Dimbleby has criticised plans to build more than 500 homes on the edge of the South Downs in Sussex.
Pelham Holdings wants to construct 520 houses, a school, shop and doctors' surgery on rural land in Polegate.
Mr Dimbleby, of Folkington, near Eastbourne, said in a letter to Wealden District Council that the scheme would destroy centuries of fine countryside.
Pelham Holdings said the need for the development outweighed his arguments.
More than 100 residents have written to the authority to object to the developer's plans.
In his letter, the 70-year-old chairman of the BBC's Question Time programme said: "It cannot be too strongly stressed that this is an area of outstanding natural beauty alongside which the proposed three storey or even two or one storey houses would be vandalism.
"As you know most of the area is about to be declared a National Park.
"While technically speaking the development is just outside the proposed boundary of the park, it is so close to it that it will inevitably damage it.
"Go to the top of Folkington Hill and look down with Pelham's proposals in your hand and you will see what I mean."
Mr Dimbleby added: "If you grant the application, you will be responsible for an act of devastation.
"Centuries of fine countryside enjoyed by thousands each year, among them many who come by train to Polegate to walk on the Downs, will be destroyed at a stroke. Please resist."
Jennifer Owen, planning consultant for the developer, said: "In the view of Pelham Holdings, planning permission should be granted.
"We have assessed the issues that Mr Dimbleby has highlighted in his letter and our view is that the need for the development outweighs any of the arguments he has put."
Wealden council is due to make a decision about Peham Holdings' planning application in early 2009.