The need for the statutory regulation of business tenancies was officially recognised towards the end of the nineteenth century. The mischief complained of was that some landlords held their tenants to ransom by demanding an inflated rent as a condition of a lease renewal. This was particularly harsh for the tenant who had built up business goodwill and carried out improvements to the premises. Despite the organisation of commercial tenants and the growth of political lobbying, it was not until Landlord and Tenant Act 1927 that controls emerged which provided compensation for loss of goodwill and improvements. The inadequacy of these provisions, however, entailed that tenant discontent and lobbying persisted until the enactment of the Landlord and Tenant Act 1954. This paper charts the social and political change which brought about this significant retreat from market forces and the gradual recognition that security of tenure, as opposed to financial safeguards, was the necessary response. The controls established in 1954 have, remarkably, survived almost intact and, subject to some fine tuning, will continue to do so. This paper addresses the issue why the commercial code has, in marked distinction to its residential and agricultural counterparts, remained immune to shifts in political policy during a sustained period of deregulation in landlord and tenant law.