## Facts

- Allied Maples Group Ltd engaged the law firm Simmons & Simmons for advice in acquiring a commercial property portfolio.
- The solicitors failed to identify and advise on certain liabilities associated with the properties in question.
- As a result, Allied Maples alleged they lost the opportunity to negotiate more favorable terms with the property vendor.
- At trial, it was found that Simmons & Simmons had breached their duty of care to Allied Maples.
- The main dispute centered on whether this breach caused Allied Maples to lose a real and substantial chance of improving their negotiating position and outcome in the transaction.

## Issues

1. Whether, in solicitor’s negligence claims, damages can be awarded for the loss of a chance to negotiate better terms, even where the outcome is uncertain.
2. Whether the claimants must prove on the balance of probabilities that a better outcome would have occurred, or only that a real and substantial chance was lost due to the defendant’s negligence.
3. How courts should properly assess causation, remoteness, foreseeability, and quantification of damages in cases involving prospective opportunities lost through professional negligence.

## Decision

- The Court of Appeal held that claimants do not need to prove that a better outcome would have been achieved on the balance of probabilities.
- It is sufficient for claimants to demonstrate a real and substantial chance that was lost due to the defendant’s negligence.
- Causation was established through the “but for” test: but for the solicitors’ negligence, the opportunity to renegotiate terms would have existed.
- The value of the lost chance was to be quantified by estimating the probability of achieving a better outcome, with damages awarded proportionally to this likelihood.
- The loss of a chance must be a foreseeable consequence of the defendant’s breach of duty.

## Legal Principles

- “Loss of a chance” is a recognized head of damage in professional negligence where the lost opportunity is real and substantial.
- In contingent loss scenarios, courts assess the probability that the claimant would have obtained the benefit, rather than requiring proof of certainty.
- Damages aim to place the claimant in the position they would have been in but for the breach.
- The doctrine extends liability in professional negligence, allowing recovery based on lost prospects rather than definite outcomes.
- The assessment of damages must involve a realistic evaluation of the opportunity lost, not speculation.

## Conclusion

Allied Maples Group Ltd v Simmons & Simmons established that, in solicitor’s negligence claims involving prospective benefits, damages for loss of a chance are available if the claimant proves a real and substantial opportunity was lost due to negligence. This principle broadened recovery for claimants, though also introduced challenges in damage assessment, and remains a central authority in professional liability cases.


Allied Maples Group Ltd v Simmons & Simmons [1995] 4 All ER 907