Construction Law in UK Law

I must say that I had thought that it is now well settled that it is not legitimate to use as an aid in the construction of the contract anything which the parties said or did after it was made. Otherwise one might have the result that a contract meant one thing the day it was signed, but by reason of subsequent events meant something different a month or a year later.

In such a case, it seems to me proper, as in the case of the carriage of goods by land, to treat the parties as having entered into the contract on the footing that Corporation would be entitled to enforce contractual rights for the benefit of those who suffered from defective performance but who, under the terms of the contract, could not acquire any right to hold McAlpine liable for breach.

It is only too easy in a complex case for a party who is dissatisfied with the decision of an adjudicator to comb through the adjudicator's reasons and identify points upon which to present a challenge under the labels "excess of jurisdiction" or "breach of natural justice". The task of the adjudicator is to find an interim solution which meets the needs of the case. The need to have the "right" answer has been subordinated to the need to have an answer quickly.

So perhaps it would be simpler to say at the outset that frustration occurs whenever the law recognises that without default of either party a contractual obligation has become incapable of being performed because the circumstances in which performance is called for would render it a thing radically different from that which was undertaken by the contract.

But in construing such a contract one starts with the presumption that neither party intends to abandon any remedies for its breach arising by operation of law, and clear express words must be used in order to rebut this presumption.

The fact that the transaction was performed on both sides will often make it unrealistic to argue that there was no intention to enter into legal relations. It will often make it difficult to submit that the contract is void for vagueness or uncertainty. Specifically, the fact that the transaction is executed makes it easier to imply a term resolving any uncertainty, or, alternatively, it may make it possible to treat a matter not finalised in negotiations as inessential.

Considerations such as these lend added weight in this context to the familiar principle of construction that clear words are needed to rebut the presumption that a contracting party does not intend to abandon any remedies for breach of the contract arising by operation of law: see, e.g., Modern Engineering (Bristol) Ltd. v. Gilbert-Ash (Northern) Ltd. [1974] A.C. 689, 717, per Lord Diplock.