Central London Property Trust Ltd v High Trees House Ltd  KB 130
Lack of consideration cam still amount to estoppel.
The defendants, High Trees, leased a block of flat from the plaintiffs, Central London Property Trust. The property suffered from falling occupancy rates due to the outbreak of World War II in 1940, so the parties agreed to reduce the rent by half. However, it was not expressly agreed how long this would last for. The defendants continued to pay the rent at this new rate. By 1945 the war had ended and the flats were at full occupancy. The plaintiffs sued High Trees for the full rent from 1945 onwards.
The defendants argued that the agreement to pay the rent at a reduced rate applied to the whole term of the lease. They argued that the plaintiffs were estopped from claiming that the rent should be higher.
The court reviewed the past case law, especially Hughes v Metropolitan Railway Co (1877) 2 App Cas 439, where the House of Lords had held that parties should be prevented from going back on a promise to waive certain rights. Denning J stated that the cases showed that a promise which the promisor knew was going to be acted on by the person to whom it was made was enforceable despite a lack of consideration. The time had come for this to be recognized as giving rise to an estoppel. Here, the plaintiffs had made a binding promise. However, the evidence showed this only applied during the war. Therefore, after the war the defendants were liable for the full rent.