Environment managers have launched a campaign to block a businessman's plans to save one of Sussex's most popular tourist spots.

Nigel Newton, the owner of Bloomsbury Books, wants to build sea defences to protect the Cuckmere Estuary, near Seaford.

The National Trust, English Nature, the South Downs Joint Committee and the Environment Agency want to stop him.

They asked for further scrutiny of a planning approval that would allow Mr Newton, whose firm publishes the Harry Potter series, to raise the banks by 30cm. If the complaint is upheld, the matter will be decided at a public inquiry.

The opposing groups are planning to let the estuary be swallowed by the sea.

They argue this will create a more natural environment for wildlife and it is wasteful to spend millions of pounds fighting coastal erosion.

But Mr Newton, whose family home overlooks the famous meanders of the river, residents and MPs say the retreat will ruin a tourist attraction visited by 350,000 people a year.

The application for the wall was approved last month by Wealden District Council and Lewes District Council, against the advice of officers.

English Nature yesterday asked for the Government Office for the South-East to ask the Secretary of State to call in the decision for scrutiny.

Chris Edwards, of English Nature, said: "The application does not have an environmental impact assessment and we are concerned the proposals could result in long-term damage to this Site of Special Scientific Interest."

Rupert Clubb, of the Environment Agency, said: "It remains unclear whether raising the banks would cause increased flood risk elsewhere. There is also the consideration that flood risks may be accelerated as a result of climate change."

Martin Beaton, of the South Downs Joint Committee, said: "We cannot go on pretending climate change is not happening or we can defend every piece of coastline. These decisions will never be easy. The return of a natural estuary will make a fantastic contribution to the natural beauty of the area."

Jonathan Light, of the National Trust, said: "We support open public discussion on all the options for the future of the Cuckmere Estuary and would welcome a formal inquiry."

Norman Baker, Lib Dem MP for Lewes, and Nigel Waterson, Conservative MP for Eastbourne, have opposed the Environment Agency's plans.

Mr Baker said: "There is considerable disquiet about the Environment Agency's plans and it is imperative these are subject to proper, rigorous and independent assessment."