When right-to-roam legislation was passed in 2003, ramblers and land reformers hailed it as a historic moment which gave ordinary citizens unrivalled access to Scotland's great outdoors. Unrivalled perhaps, but not unrestricted.

When right-to-roam legislation was passed in 2003, ramblers and land reformers hailed it as a historic moment which gave ordinary citizens unrivalled access to Scotland's great outdoors. Unrivalled perhaps, but not unrestricted.

Yesterday's landmark legal judgment in favour of Ann Gloag, the Stagecoach millionaire and owner of a multi-million pound Perthshire estate, goes some way towards setting out the boundaries across which walkers cannot expect to pass.

In a bitter blow to the Ramblers Association and Perth Council, who had contested the action, Sheriff Michael Fletcher ruled that there were areas of Ms Gloag's 28-acre estate around Kinfauns Castle which could legitimately be excluded from public access.

He found that the 7ft fence she had erected around a 12-acre enclosure surrounding the castle was legitimate, given her fears over security and the need to pursue a private life enshrined in the European Convention of Human Rights.

The case was billed as a showdown between ordinary ramblers and one of Scotland's richest women. Former nurse Mrs Gloag, 64, made her fortune with the success of the Stagecoach bus firm she founded with her brother Brian Souter.

The Sunday Times Rich List this year estimated the pair's fortune at around £770m.

Perth Sheriff Court heard that Mrs Gloag's home was often used to entertain high-profile business people and celebrities.

Her high profile put her at risk from criminals who could conceivably kidnap members of her family and media - especially tabloid newspapers - who were likely to want to intrude on her privacy, it was argued.

But though the themes of access vs privacy were writ large, the specifics of the case hinged on a fairly detailed assessment of the area that Ms Gloag could reasonably expect to be considered private and therefore exempt from the access right enshrined in the Land Reform (Scotland) Act 2003.

At one point in the case, which began last October, this question led the sheriff to don wellington boots and trudge around the estate followed by an entourage of lawyers, council officers, ramblers and journalists.

The 34-page judgment reflects the complications of the point: several pages are dedicated to exploring whether children's play equipment had been placed in woodland simply for the benefit of the court, to give a misleading impression that it required a high level of privacy. There is also a detailed discussion of the viability of a proposed barbecue area and renovation work to restore overgrown areas of woodland.

Though the sheriff ruled that the play equipment had, on balance of probabilities, been placed there for the benefit of the court action, he discounted ramblers' claims that areas of overgrown woodland should not be considered a private area as plans were afoot to redevelop them.

However, the implications of the ruling go far beyond the specific geography of Kinfauns Castle and are likely to set the stage for future conflicts between ramblers and estate owners.

Sheriff Fletcher was critical of claims by the Ramblers' Association that 95% of people taking access to the countryside did so in a reasonable way, ruling that some may not be there to enjoy the countryside but have "ulterior criminal or voyeuristic motives".

He was particularly critical in his judgment of David Morris, director of the Ramblers' Association Scotland, who he said had walked across parts of Ms Gloag's estate "in the teeth of opposition by the land manager" then successfully persuaded police - erroneously - that the question of access was a civil, rather than a criminal, matter.

This, he said, was not in keeping with the Land Reform Act and set a poor example to those who sought to interpret right-to-roam legislation responsibly.

"If that were the way the act is put into effect by a person such as the director of the Ramblers' Association, what can one expect of others whose experience of the code and workings of the act is much less developed?" he asked in his judgment.

One of the culprits of this misinterpretation was the Scottish Outdoor Access Code, published by Scottish Natural Heritage, which sets out the rights and responsibilities of landowners and ramblers, Sheriff Fletcher found. He said it gave a misleading impression weighted in favour of those seeking access and did not accurately reflect the legal rights of landowners to expect privacy when seeking exemptions from right-to-roam legislation.

A detailed examination of the law revealed "a more liberal approach to the amount of land to be excluded" than the Ramblers' Association had proposed, Sheriff Fletcher said.

People living in country estates would have their enjoyment of their homes reduced if it were not located in "reasonably large grounds which were private" and so exempted from access rights, the sheriff ruled.

Though this is the first case to test the right-to-roam legislation, it will not be the last. The Ramblers' Association said yesterday it was considering the details of the ruling and had not ruled out an appeal.

Meanwhile, another millionaire businessman is awaiting a separate legal ruling which will decide whether ramblers and walkers can be excluded from his entire 70-acre estate at Boquhan, near Kippen in west Stirlingshire.

Euan Snowie and his wife Claire claimed the right-to-roam legislation interfered "with their children's right to ride their ponies in peace".

Though the right to roam is still very much alive after this case, it has not emerged entirely unscathed. Just how many Keep Out signs have to be dug up and replanted, though, is yet to be seen.