Promissory estoppel has yet to be explored fully in the light of decided
cases, and some issues remain a little uncertain. Debate has taken place
about whether original rights are extinguished or merely suspended. Lord
Denning favoured the former view in the case of Alan v El Nasr (1972),
where he said that the creditor’s strict legal rights were not to be enforced
later, basing this on the argument that the other party may be unable to pay,
having altered his position as a result of the promise. A more cautious view
is generally taken by the majority of the judiciary, the House of Lords
favouring the suspension of rights (as in Hughes) in the case Tool Metal
Manufacturing Co Ltd v Tungsten Electric (1955). The Privy Council
expressed the view in Emmanuel Ayodei Ajayi v Briscoe (Nigeria) Ltd
(1964) that the promise only becomes final and irrevocable if the promisee
cannot resume their original position. This seems a reasonable position,
since the whole doctrine is based on equity, and perhaps will provide a
reconciliation of these opposing views.
Another issue which has caused debate is whether the promisee must have
acted to his detriment to use the doctrine as a defence successfully. This
was an important factor in Hughes, but again Lord Denning posed an
alternative view in saying in Alan v El Nasr (1972), and more recently in
Brikom Investments Ltd v Carr (1979), that the element of detriment is not
strictly necessary.
62 Contract law
requested by cheque, and the plaintiff sued for the rest. The defendant
claimed promissory estoppel, arguing that in accepting the cheque the
builders had agreed to payment of part of the debt. The court, however,
felt that the builders had been held to ransom, being forced to take what
they could, and awarded judgment in their favour. In the circumstances
it would have been inequitable to allow the defendants to succeed in a
claim of promissory estoppel, as the whole idea of equity is to do
justice (he who seeks equity must do equity).Consider the following situation. Jim borrows money from Kate, but then
finds that he cannot work for the next few weeks because his mother is
seriously ill in Japan and he needs to visit her. On hearing this Kate says ‘I will
let you off the rest of your debt, if it means that you can visit your mother
with an easy conscience.’ Jim is very grateful and goes to Japan. Six weeks
later he returns to England and wins the lottery. Should Jim be able to rely
on promissory estoppel, or should Kate now be able to enforce full payment?