I want to start from the basic position in which I was brought up (I expect you were all brought up in it too) that the terms of a contract consist of conditions and warranties, the distinction between them being that the condition is something that is essential to the contract, while the other terms that are collateral or ancillary are merely warranties. If a condition is broken the aggrieved party is discharged from his obligations and can rescind the contract. If it is a warranty that is broken, the breach sounds only in damages.
The Hongkong case—a new approach to breach
The traditional thinking on this point has recently been rather mystified by references to something which is called the fundamental term and which has not yet, so far as I know, been judicially defined. Then there have been some suggestions that what matters is not the fundamental term but the fundamental breach. And finally there is the very important judgment of Diplock L.J. in the Hongkong case in which he opens up new vistas, suggesting that the traditional classification of terms into conditions and warranties has been outmoded and ought to be scrapped in favour of a new approach altogether based on the event.
It must be accepted that whatever sort of approach is made to this topic, whether a new or a traditional one, there must be some way of defining the situation in which the aggrieved party is entitled to rescind. He cannot be allowed to do so for every breach of every term.