One of Sussex's most famous gardens could struggle to survive if ramblers are given free access, its owner has warned.

Walkers would be free to roam the heathland that forms the deer and wallaby park at Leonardslee Gardens at Lower Beeding, near Horsham, according to provisional maps.

More than 200 acres of heath around Hogstolt Hill are marked as open country on the most recent maps, published by the Countryside Agency.

Heathland, such as that at Leonardslee, which has been part of the gardens for more than 100 years, is accessible to the public under new right-to-roam laws, along with mountains, moorland, downland and registered common land.

The amount of proposed access land at the gardens is about half what was originally proposed but would still enable people to enjoy the scenery without paying the usual entrance fee.

Owner Robin Loder said: "There is no way we can live with this. It just destroys the viability of the garden.

"The area they have earmarked, particularly during the summer months, is one of the most beautiful and attractive areas of Leonardslee.

"Unless we can defeat this, it could mean the end of the garden. It would certainly mean the end of the financial viability of the garden, which is the same thing."

Landowners can propose changes to the maps during an appeal period that runs until late October.

Mr Loder said: "We don't know whether the threat to us is minor or huge. We are a bit of a guinea pig. At the moment we don't really know where we stand."

According to walkers, the maps, which have been published following a public consultation that closed earlier this year, contain few major changes.

About three per cent of the Downs that does not already have public access would be opened up, much of it in small isolated fragments.

They say the fragments, many of them on the steep north facing scarp slope, need to be linked if right-to-roam is to have any significant effect on the Downs.

The South-East is one of the first two regions where access land under the new laws is being identified, although it may be 2005 before walkers win access rights.