The Claimant, a retired miner, sued his former solicitors, alleging professional negligence in handling his claim for Vibration White Finger because they had not made a claim for a Services Award on his behalf. The trial judge conducted a "trial within a trial” to ascertain whether the Claimant would have been succeeded in obtaining a Services Award, had his solicitors pursued that claim. The trial judge found the Claimant's evidence unreliable and concluded that had the Claimant’s solicitors pursued a Services Award on his behalf, it would not have succeeded. The defendant appealed against the trial judge’s approach.
The court held that it was not wrong in law or in principle for the trial judge to have conducted a trial of the question of whether the Claimant would, or could, have brought an honest claim for a Services Award. That was something that the Claimant had to prove on a balance of probabilities, and for which a trial was the appropriate means of evaluation.
Referring to the “sensible, fair and practicable dividing line” that was laid down in the case of Allied Maples Group Ltd v Simmons & Simmons (a firm)  1 WLR 1602, the court noted that:
“… the courts have developed a clear and common-sense dividing line between those matters which the client must prove, and those which may better be assessed upon the basis of the evaluation of a lost chance. To the extent (if at all) that the question whether the client would have been better off depends upon what the client would have done upon receipt of competent advice, this must be proved by the Claimant upon the balance of probabilities. To the extent that the supposed beneficial outcome depends upon what others would have done, this depends upon a loss of chance evaluation.”
In the case of a failure of a solicitor to advise the Claimant he had a good claim, the Claimant must prove on the balance of probabilities that he would have pursed the claim if advised properly and that he could have done so honestly. This judgment represents an important clarification of the burden of proof in such claims.
In these situations, the court occasionally departs from the ordinary burden on a Claimant to prove facts on the balance of probabilities. It does so by recourse to the concept of loss of opportunity or loss of a chance. But that does not mean that the Claimant does not still have the basic requirement to prove that their loss is caused by a breach of duty.
These principles apply equally to claims for the loss of an opportunity to achieve a more favourable outcome in a negotiated transaction, and to claims for the lost opportunity to pursue a legal claim.