CA 25 February 1987. An appeal by landlords, seeking a declaration as to the construction of a rent review clause in an underlease of premises on an industrial estate. The 25-year lease was subject to four five-yearly reviews. In August 1985, the landlords, then Smiths Industries plc, gave notice to the tenants to negotiate the "full yearly market rent" - rent at which the property might reasonably be expected to be let on the open market. There was no express reference to a "willing lessor" or to a "willing lessee". The tenants contended there should be no assumption that there would be a willing lessee to whom the property might reasonably be expected to be let. The parties could not reach agreement, and an independent valuer was appointed. Landlords submitted that the valuer should determine the rent which would be expected to be agreed between a willing lessee and a willing lessor. The ChD judge concluded that to say that it must be assumed that there will be a letting, is to inc