Equitable Estoppel in UK Law

Moreover the fundamental principle that equity is concerned to prevent unconscionable conduct permeates all the elements of the doctrine.

It can be said that there is a case for reform of the law, which has to be discovered in a number of diverse rules based on no coherent line of reasoning.

Proprietary estoppel typically consists of asserting an equitable claim against the conscience of the "true" owner. It is to be satisfied by the minimum award necessary to do justice ( Crabb v Arun District Council [1976] Ch 179, 198), which may sometimes lead to no more than a monetary award. A "common intention" constructive trust, by contrast, is identifying the true beneficial owner or owners, and the size of their beneficial interests.

Estoppel by deed is a rule of evidence founded on the principle that a solemn and unambiguous statement or engagement in a deed must be taken as binding between parties and privies and therefore as not admitting any contradictory proof. It is important to observe that this is a rule of common law, though it may be noted that an exception arises when the deed is fraudulent or illegal.

In such a case the court's natural response is to fulfil the claimant's expectations. But if the claimant's expectations are uncertain, or extravagant, or out of all proportion to the detriment which the claimant has suffered, the court can and should recognise that the claimant's equity should be satisfied in another (and generally more limited) way.

An "estoppel" bars the object of it from asserting some fact or facts, or, sometimes, something that is a mixture of fact and law, that stands in the way of some right claimed by the person entitled to the benefit of the estoppel. The estoppel becomes a "proprietary" estoppel - a sub-species of a "promissory" estoppel - if the right claimed is a proprietary right, usually a right to or over land but, in principle, equally available in relation to chattels or choses in action.

Here it is being used (as in my opinion it should always be used) as an objective value judgment on behaviour (regardless of the state of mind of the individual in question). As such it does in my opinion play a very important part in the doctrine of equitable estoppel, in unifying and confirming, as it were, the other elements. If the other elements appear to be present but the result does not shock the conscience of the court, the analysis needs to be looked at again.