Three mechanisms, very different reach
English law deals with changed circumstances through three distinct mechanisms. Frustration is a common law doctrine that automatically discharges a contract when performance becomes impossible, illegal, or radically different - but it operates within narrow limits and never applies merely because performance has become harder or more expensive. Force majeure is purely contractual: unlike civil law systems, English common law has no inherent force majeure doctrine, so protection exists only where the contract provides it. Hardship - where performance is still possible but excessively onerous - has no general relief under English law at all.
So the three differ sharply in reach: frustration is automatic but rare; force majeure is whatever the clause says; hardship is unprotected unless expressly drafted for.
The default: the affected party bears the risk
The practical consequence is stark. Without appropriate contractual provisions, a party bears the risk of changed circumstances entirely. Economic hardship, supply-chain disruption, currency moves, and dramatically increased costs will not excuse performance. As the courts have repeatedly held, a contract becoming expensive - even dramatically more expensive - to perform is not a ground for relief.
English law's instinct is pacta sunt servanda: agreements are kept. Relief for changed circumstances is the exception, and largely one the parties must build themselves.
Why drafting decides the outcome
Because force majeure has no inherent meaning and hardship no general doctrine, the contract does almost all the work. Every element of protection - which events count, what causal link is required, what notice must be given, and what happens next (suspension, termination, renegotiation) - has to be specified. A missing or loose clause is not interpreted generously; it is read strictly, and gaps fall on the party seeking relief.
Frustration sits in the background as a narrow safety net, but a comprehensive force majeure clause covering the event usually displaces it - because the parties are then taken to have contemplated and allocated that risk.
What changed recently
The leading recent authority is MUR Shipping BV v RTI Ltd [2024] UKSC 18, where the Supreme Court held that a reasonable-endeavours proviso in a force majeure clause does not require a party to accept non-contractual performance, even where it would suffer no detriment. A party entitled to payment in one currency need not accept another; a party entitled to delivery at one port need not accept another.
The COVID-19 and sanctions era also produced extensive litigation, and recent cases show how high English law's thresholds are - a reminder that express, up-to-date drafting (pandemics, sanctions, climate events) is now essential.
How to use these guides
Treat changed-circumstances risk as something to allocate deliberately. The supporting articles cover: frustration and its narrow limits; force majeure clauses and how the courts read them; drafting a force majeure clause that works; hardship and the renegotiation mechanisms English law will not supply for you; and how force majeure and frustration interact.
The discipline is the familiar one: English law will not rescue you from a bad bargain or a changed market, so build the relief you want into the words before you sign.
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Practical checklist
- Assume no automatic relief for changed circumstances - allocate the risk in the contract.
- Do not expect frustration to help with mere added cost or difficulty - its limits are narrow.
- Include an express force majeure clause - English law implies none.
- Add a separate hardship clause if you want relief for excessively onerous (but still possible) performance.
- After MUR Shipping [2024] UKSC 18, do not assume reasonable endeavours forces acceptance of non-contractual performance.
- Update event lists for pandemics, sanctions, and climate events; draft, do not rely on doctrine.
This guide is informational only and is not legal advice. It does not replace advice from licensed counsel on the facts of a specific transaction.
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