Ajayi v Briscoe [1964]

There is an equitable principle of promissory estoppel that, when one party to a contract agrees in the absence of fresh consideration not to enforce his rights, an equity will be raised in favour of the other party. This equity is, however, subject to the qualifications:

(1) that the other party has altered his position;

(2) that the promisor can resile from his promise on giving reasonable notice, which need not be formal notice,…