Dismayed businesses, environmentalists and community organisations have been told they may have to wait months for a decision on the South Downs National Park.

The Department for the Environment, Food and Rural Affairs says deliberations have been put on hold indefinitely because of legal wrangling.

Letters have been sent to all groups waiting for the outcome of the process already nearly four years overdue. The decision on whether Sussex and Hampshire's chalk downs would be made a National Park was originally expected by 2002/3. More recently people expected an announcement next month. Now it is unlikely before the autumn.

Chris Todd, campaign officer for the South Down Campaign, said: "When we first started we were told 2002 to 2003. I was employed for two years. I am approaching six years.

"We want to have a National Park with the funding and protection it deserves without the landscape being constantly under threat even though people are trying to protect it."

The delay has been caused by a ruling in an appeal against the boundary of the New Forest National Park. The owners of a stately home argued that their 6,000-acre parkland should not be included.

A judge ruled in their favour, saying National Parks must be areas of rugged "natural beauty", not agricultural or managed park land.

Defra wants to challenge this ruling, saying all of England's countryside has been shaped by humans.

Stephen Eastman, of Hove architects the Miller Bourne Partnership, is appealing against the inclusion of some land at Southwick in the South Downs National Park area.

The firm, acting for a London developer, argues that the use of the land, formerly part of Hill Farm, should be decided by the community. Mr Eastman said: "We had been expecting a result fairly quickly. It is taking a very long time."

In the meantime, an amendment has been made to the Natural Environment and Rural Communities Bill about to go through Parliament, giving "natural beauty" a wider definition.

The Defra spokeswoman said: "The High Court judgement has taken an unusual slant on 'natural beauty' which would affect existing parks and have ramifications for the South Downs."