## Facts

- Mr. Gregg consulted Dr. Scott regarding a lump under his arm.
- Dr. Scott negligently misdiagnosed the lump as benign, leading to a nine-month delay in proper treatment.
- During the delay, the cancerous tumor progressed significantly.
- At trial, expert evidence showed that with prompt diagnosis, Mr. Gregg's chance of survival would have been approximately 42%, which dropped to 25% after the delay.
- The central issue was whether the reduction in survival prospects constituted a compensable loss as a loss of a chance.

## Issues

1. Whether a claimant can recover damages for loss of a chance of a better outcome where a defendant's negligence reduces survival prospects below 50%.
2. Whether the reduction in the prospect of survival due to delayed diagnosis constitutes a distinct and compensable head of damage.
3. Whether the principle of causation should be extended to permit proportionate recovery in cases where definitive proof of causation is problematic due to medical uncertainty.

## Decision

- The House of Lords by a 3-2 majority held that loss of a chance is not a recoverable head of damage in medical negligence.
- The majority (Lord Hoffmann, Baroness Hale, and Lord Phillips) refused to extend causation to permit damages for reduced chances of a favourable outcome.
- Lord Hoffmann noted difficulties in defining the relevant injury and distinguished evidential from medical uncertainty.
- Baroness Hale cited practical and policy concerns regarding the complexity and predictability of a proportionate damages system.
- Lord Nicholls and Lord Hope dissented, arguing a significant lost chance is still a compensable harm.
- The appeal was dismissed, upholding the requirement to prove causation on the balance of probabilities.

## Legal Principles

- Causation in negligence traditionally requires proof on the balance of probabilities that the defendant's breach caused the harm.
- Loss of a chance is not a recognized head of damage in medical negligence when the chance was below 50% at the outset.
- Proportionate damages for loss of chance are generally unavailable except in certain cases (e.g., third-party actions or special circumstances as in mesothelioma/asbestos exposure).
- Policy and practical concerns were essential to maintaining the orthodox causation approach.
- The decision confirmed and followed the precedent in Hotson v East Berkshire Area Health Authority [1987] AC 750, distinguishing exceptions such as Fairchild v Glenhaven Funeral Services Ltd [2002] UKHL 22 and Perry v Raleys Solicitors [2019] UKSC 5.

## Conclusion

The House of Lords reaffirmed the traditional causation test in negligence, holding that damages are not recoverable for loss of a chance of a better medical outcome. This approach, influenced by policy and practical concerns, remains authoritative except for narrow exceptions involving third-party actions or specific conditions such as mesothelioma.


Gregg v Scott [2005] 2 AC 176