When a developer bought a piece of land, intending to build an office block, it was in for a shock. The land benefited from an easement granting access over adjacent land (the garden of a house). This allowed the right of passage of utility companies over and through the adjacent land.
The developer applied to electricity company EDF to put in an electricity supply to its land, which required EDF to lay cables through the adjacent land. EDF refused to do so unless the owners of that land signed a deed granting it the right to lay the cables. The landowners refused.
The developer went to court, claiming that the landowners were obliged to give the grant to EDF. The claim failed. An easement has a negative character: it prevents something. The landowners could not stop EDF. However, an easement cannot compel the person(s) granting it to do something; in this case, it could not compel the landowners to give EDF the deed it demanded.