The "estate in fee simple" title granted by the Crown, under which land is held not owned, by definition implies an obligation. Fee is a derivative of fief or trust originally granted by the King to certain Barons in return for services to be rendered in time of battle, on demand, or on state occasions—an acknowledgement of the trust.

About the time of Runnymede (1215) the Barons not only curtailed the King's tyrannical rule without trial but at the same time entrenched their privilege by satisfying their obligations in other ways e.g. a beer tax, other levies on the poor and later the enclosure (privatisation) of the Commons. This privilege which the Barons arrogated to themselves has become entrenched and fragmented until today it is bought and sold as the freehold title i.e. the right to claim the economic rent, with income and other taxes in lieu, progressively enshrined in statute.

So the "estate in fee simple" is essentially a holding on trust, without specified obligations, conditions or terms i.e. an open ended leasehold which can be inherited without constraint.

This basic status readily admits the inclusion of more stringent terms such as Town Planning ordinances, environmental regulations and the like, as terms of the lease which recognise and give effect to the fundamental social relationship—the Crown and the subject; the community and the individual; landlord and the life-tenant. A lease also sets out the rights of the lessee i.e. the rights and responsibilities of both parties.