This is a contractual provision within a lease, that specifies the use, or uses to which a property may be put and the uses which are prohibited. The formal classification of “Uses” are set out in the Town and Country Planning (Use Classes) Order 1987 as amended, which is a statutory instrument defining various use classes.The terminology of a user clause contained within a lease is critical in determining whether the use specified is restrictive or open. This aspect can be very important when considering the open market rental value of a property.