Health warning :Complete novice at the law.
However at the back of my mind I think I heard once that the long use of a footpath etc., can be used to establish a right of Way.
A quick web search produced the term 'easement'
quoting from
http://www.boundary-problems.co.uk/maineasements.htm"An easement is a right benefiting one piece of land (known as the dominant tenement) that permits the rightful users of that land to perform specified actions over an adjacent piece of land (known as the servient tenement). Probably the most commonly used easement is one that allows the underground services (water, drainage, gas, electricity, telephone and TV cables, etc) of one property to pass beneath the land of one or more neighbouring properties. Perhaps the most widely known easement is the private right of way. There are others, such as the right to light, right of support."
and
"An easement may also be created "by prescription". This happens when someone carries out an act (that is capable of being an easement) repeatedly, openly and without the (potentially servient) landowner's permission for a period of least twenty years. "
more information at
http://www.landreg.gov.uk/assets/library/documents/lrpg052.pdf
