Professor Janet O’Sullivan delivers a seminar on “Puzzles in the Law of Economic Duress and Lawful Act Duress”

On 8 April 2025, Professor Janet O’Sullivan from the University of Cambridge delivered a lively and thought-provoking lecture on “Puzzles in the Law of Economic Duress and Lawful Act Duress”, hosted by the EW Barker Centre for Law & Business at NUS Law. Drawing from a range of leading cases, academic commentary, and practical examples, Professor O’Sullivan explored two central puzzles in contract law: the role of threats to breach a contract, and the controversial doctrine of lawful act duress.

She began with a vivid illustration — the “wedding caterers” scenario — to anchor discussion on the fundamental components of economic duress: an illegitimate threat, causation, and the absence of reasonable alternatives. A key question she posed was whether every threat to breach a contract should be seen as illegitimate. While some courts and commentators argue that a good faith threat might be permissible, Professor O’Sullivan strongly rejected this view, emphasising the need to protect the certainty and sanctity of contractual obligations.

The lecture delved into notable cases including B & S Contracts and Design Ltd v Victor Green Publications Ltd, DSND Subsea v Petroleum Geo Services, and Times Travel v Pakistan Airlines, the latter serving as a springboard for examining the limits of lawful act duress. Professor O’Sullivan critically assessed the Supreme Court’s approach in Times Travel, questioning whether the doctrine should even exist as a separate category, since Lord Hodge’s two examples involve independent wrongdoing aside from a lawful threat, while Lord Burrows’ ‘bad faith’ example of a defendant misrepresenting its belief that the claim being waived is not valid would be better addressed through the law of misrepresentation.

She concluded by defending a relatively expansive doctrine of economic duress, arguing that the law should offer robust protection against coercive commercial practices — especially where unequal bargaining power and last-minute renegotiations threaten to undermine contractual fairness.

The event concluded with an engaging Q&A session, where the attendees discussed the implications of these doctrines for contemporary contract law, particularly in light of commercial realities, negotiation dynamics, and comparative approaches.

Professor Janet O’Sullivan presenting

(From left) Professor Janet O’Sullivan (University of Cambridge) and Professor Mindy Chen-Wishart (NUS Law)