Harry Sanderson (Brasenose College Oxford) has posted Wavering between a Rock and a Hard Place: The Future of No-waiver Clauses in English Law ((2021) 37 Journal of Contract Law 122) on SSRN. Here is the abstract:
A recent decision of the United Kingdom Supreme Court, Rock Advertising Ltd v MWB Business Exchange Centres Ltd [2019] AC 119, held that compliance with form requirements for contractual modification is mandatory, and that non-compliant agreements are ineffective. The decision has drawn significant criticism for its approach to the law of contractual modification. This article looks beyond contractual modification and posits that the decision has implications for the law of waiver. It argues that the rule established by the Supreme Court requires that form requirements for waiver must be strictly enforced, a reversal of the current position. It contends that such a situation is undesirable, but nonetheless preferable to a situation in which ‘no oral modification’ clauses are strictly enforced, but ‘no-waiver’ clauses are not.