In Platt v London Underground Ltd ( WL 172012) LUL granted a lease of a kiosk to P. The kiosk was in the exit from an underground station. Only people leaving the station through that exit (there was another) would use the kiosk. P claimed that LUL only allowed passengers to use the relevant exit during the morning rush hour and at no other times. Thus, the kiosk was starved of trade. P succeeded in his claim that LUL had acted in derogation from grant.
The surrounding circumstances at the time of the grant were a strong indicator as to what the parties must have had in their mutual contemplation. The kiosk relied on passengers going through the exit as its only source of customers. At the time of the lease, the exit was open for much of the time. This was plainly important to the tenant. There was nothing in the circumstances at the time of the grant or in the communications between the parties, or in the express terms of the lease to indicate that P had accepted a risk that the exit might be closed most of the time. The parties had contemplated that the exit would be part of the station operation during the opening hours of the station. Closure of the exit for much of the time during the lease did amount to a derogation from grant.
Neuberger J. provided some commentary on the law concerning derogation from grant. There is a ”very substantial degree of overlap, between the obligation not to derogate from grant, the covenant for quiet enjoyment, and a normal implied term in a contract.’ (p. 5)
He endorsed the approach of Bowen L.J. in Myers v. Catteson ((1889) 42 ChD 470 at 481) who said that the aim of the covenant is to give effect to, ’the obvious intention of the parties, so as to give the transaction between them a minimum of efficacy and value which upon any view of the case it must have been their common intention that it should have.’
The judgment contains a set of principles concerning non-derogation from grant (pp. 4 – 8). The express terms of the lease and the surrounding circumstances at the date of the lease will be highly relevant in determining whether an act amounts to a derogation from grant. Where the action complained of is the use of the landlord’s retained land, the tenant cannot complain of uses to which the retained land could reasonably be put after the grant of the lease.
‘When assessing what the parties to a contract actually or must have contemplated, one should focus on facts known to both parties and statements and communications between them. A fact which could only have been known to one party could not, save in very unusual circumstances, be a legitimate part of the factual matrix. A thought locked away in the mind of the parties, or even perhaps of both parties, cannot normally be a relevant factor when assessing the parties’ understanding. In English law at any rate, contract is concerned with communication as well as mutuality’.