A contract procured by duress or undue influence is voidable rather than void, so everything turns on whether rescission is available and whether anything has barred it. This chapter opens with the common ground between the two doctrines and the recognised categories of duress, then works through the elements of economic duress — illegitimate pressure, causation and the absence of any reasonable alternative — and the four bars to rescission, including affirmation and third-party rights. It then distinguishes actual from presumed undue influence, covering the relationships that automatically raise the presumption, what makes a transaction call for explanation, and how the presumption may be rebutted, with independent legal advice neither the only route nor automatically enough. It closes with the three-party problem in lending: when a lender is put on inquiry, the steps required to avoid constructive notice, and what the solicitor advising the surety must cover.
