A recent court decision is a reminder of sloppy drafting in leases leading to bizarre outcomes.

A valid lease must be granted for a "term certain" or on a periodic basis. In this case an occupancy agreement between a mutual housing association and one of its members was expressed to be "from month to month until determined". The agreement set out defined means of termination; either by the tenant giving one month's written notice or under defined circumstances in which the landlord could end the agreement, not including a simple notice to quit.

The agreement, although incapable of being a tenancy due to its uncertain duration, was treated as a tenancy for life at common law, taking effect as a 90 year lease determinable either on the tenant's death or in accordance with its express provisions.

This outcome is hardly likely to be what the parties intended. Further, the court's legal basis for turning the agreement into a tenancy for life would not have been possible had the tenant been a company, where the rule against uncertainty would have left the lease wholly invalid.

A lease of business premises may only be excluded from security of tenure if it is granted for a "term certain". Sloppy drafting in these cases can result, and has done, in granting more security of tenure than the parties intended.

The Supreme Court has called for a Law Commission review of the certainty of term rule, and for its abolition by Parliament.

Further details of the case Berrisford v Mexfield Housing Co-operative Ltd (Rev 1)(2011) can be found here.