Professional Negligence UK: Causation & Loss Explained

Overview

Professional negligence is where a person providing professional services falls short of the standard of care expected of a reasonably competent member of their profession, and that failure causes harm to the client or, in some cases, a third party. Establishing a breach of duty is only the first hurdle.

The claimant also has to link the breach to a real, measurable loss. Causation is the legal bridge between the wrong and the damage. Loss is the value of what the claimant has been put out of pocket or otherwise deprived of.

Without both, a claim will not succeed, even where the professional's conduct was clearly poor. The courts look at causation through several lenses, including the 'but for' test, material contribution, and whether the loss was a foreseeable consequence of the breach.

Damages are then assessed with the aim of putting the claimant in the position they would have been in had the negligence not occurred.

Key steps

1. Identify the duty and the breach. Before causation comes into play, you need to be clear on the duty the professional owed and how they fell short. This might be set out in a retainer, an engagement letter, or implied by the relationship. Compare what happened against what a reasonably competent professional would have done in the same circumstances.
2. Apply the 'but for' test. Ask whether, but for the professional's failure, the loss would have happened anyway. If the answer is that the loss would have occurred regardless, factual causation usually fails. This is an objective assessment and often turns on what a hypothetical competent professional would have advised or done instead.
3. Consider material contribution. In some cases, the negligence is one of several causes. Where it is difficult or impossible to separate the effect of each cause, the courts may accept that the breach materially contributed to the loss. The contribution has to be more than trivial, and expert evidence is often needed to establish it.
4. Check foreseeability and remoteness. Even where factual causation is made out, the loss must not be too remote. The type of damage needs to be something a reasonable professional could have foreseen as a likely consequence of getting it wrong. Unusual or freak losses may fall outside the scope of recoverable damages.
5. Quantify the loss. Loss can include wasted fees, the difference in value between what you got and what you should have received, lost profits, tax liabilities, or the cost of putting things right. Non-financial losses such as distress may be recoverable in narrower circumstances. Keep records, invoices, valuations, and correspondence to support the figures claimed.

Common questions