The boundary shown on the filed plan to the registered title of a property is a general boundary and does not determine the exact line of the boundary. Of course property lawyers know this but it is not necessarily known to by property owners. Even if you are familiar with the concept of this general boundary rule you may not appreciate some of its consequences.
For instance, even if an adjoining landowner proves that the boundary line is inaccurate and that he does own land within the boundary of a registered title he may not succeed in having the boundary changed. This is because the boundary shown on the filed plan is a general boundary and if it were altered it would still be a general boundary, albeit drawn in a different place. Thus, altering it would not change the ownership of the land. Having said that in such circumstances a change would probably be made.
Another more recent example concerning the ownership of land adjacent to a boundary related to a claim for a prescriptive right of way (an easement) over a driveway. The user of the driveway succeeded in proving that he had used the driveway for more than 20 years. However, his neighbour claimed that he was not entitled to a right of way because, for a time, part of the driveway had been registered within the user's registered title (but this had changed when the boundaries were altered on the application of all interested parties who acknowledged that the title plan wrongly showed the boundary) and a person cannot acquire an easement over his own land.
The adjudicator to HM Land Registry decided that the alteration of the filed plan made the general boundary more accurate but did not effect a transfer of ownership. The driveway had always been outside the ownership of the user and so his claim for the easement succeeded.