A restriction contained in a legal document which limits the rights of a person having an interest in the land but, by its wording envisages the possibility of removing the limitation on terms agreed between the parties eg. a covenant by a lessee not to assign or sublet without the landlord’s written consent. In certain cases, such as the one quoted, statute law strengthens the applicant’s position by importing such words as “such consent not to be unreasonably with-held”.