Assessing loss of a chance

17 Nov 2014

In Chweidan v Mischon de Reya Solicitors [2014] EWHC 2685 (QB) Mrs Justice Simler considered the principles to be applied when assessing claims for loss of a chance and provided a helpful overview of a number of the leading authorities.

The employment tribunal claim

Mr Chweidan was employed by JP Morgan Europe Limited (“JP Morgan”) until he was made redundant in July 2008. He brought an employment tribunal claim against JP Morgan and instructed Mischon De Reya Solicitors to represent him, complaining that he had been discriminated against because of his age and his disability, which resulted from an accident in 2007 whilst on a work skiing trip.  Despite the accident, Mr Chweidan’s performance had improved from the previous year, but he was given a significantly lower bonus. Mr Chweidan alleged that he was told by managers that JP Morgan were taking a bet on younger staff.

The tribunal found that Mr Chweidan had been unfairly dismissed and that JP Morgan had unlawfully discriminated against him on the ground of his disability in respect of his bonus payment and by dismissing him; he was awarded compensation of £586,059.09

JP Morgan appealed, challenging the finding of unlawful direct disability discrimination. Counsel prepared a cross-appeal, but advised that it was weak and that Mr Chweidan could be ordered to pay some of JP Morgan’s costs. The cross-appeal was lodged late and an application to extend time was dismissed.

Mr Chweidan ultimately succeeded in respect of his unfair dismissal claim only and recovered £68,000 odd, but had a costs liability which exceeded that sum.  He then brought a claim for professional negligence against Mischon De Reya, which specifically raised failure to lodge the cross-appeal in time, alongside other complaints about the conduct of his claim.

The professional negligence action

Mischon De Reya admitted breach of duty in relation to failure to lodge the cross-appeal in time, but asserted that Mr Chweidan had not lost an opportunity of any value because the grounds of cross-appeal had no more than a negligible prospect of success. On the issue of the cross-appeal, Mrs Justice Simler said that she needed to determine:

(i) If Mr Chweidan had more than minimal prospects of success on appeal in relation to any of his grounds and if so which?

(ii) If Mr Chweidan had a more than minimal prospect of success in any remitted claim before an employment tribunal, and, if so, the most probable value of the claim and the overall chance of success.

Mrs Justice Simler noted that even if the cross-appeal had been lodged in time, its fate would have depended on a number of factors, including:

(i) Whether or not the cross-appeal would have been permitted to proceed beyond the Employment Appeal Tribunal (“EAT”) paper-sift as raising an arguable point of law.

(ii) Whether or not the appeal would have succeeded and led to a remission of the issues raised to an employment tribunal.

(iii) The credibility of Mr Chweidan.

(iv) The witnesses called for JP Morgan and their performance in the witness box.

(v) the availability of further disclosure.

(vi) the decision taken by the employment tribunal determining the issues which would then have arisen between Mr Chweidan and JP Morgan.

Mrs Justice Simler said that unless the prospects of success were so poor as to be negligible, she needed to assess the chance of Mr Chweidan ultimately succeeding in recovery an award of compensation in the litigation or by way of settlement. 

Notwithstanding contemporaneous negative assessments of the prospects of success, Mrs Justice Simler said that the prospects of success were more than negligible; doing the best she could on the information available, she concluded that Mr Chweidan had a slightly less than 50% chance of success on the cross-appeal and a one third chance of success in the underlying claim following the appeal.  These two percentage chances were multiplied, producing an overall percentage chance of success of just under one sixth (15% – 16%). A slight uplift was applied because JP Morgan may have viewed the litigation differently if Mr Chweidan was successful on appeal; Mrs Justice Simler emphasised that the assessment is not “a purely mathematical or mechanical exercise.  Although the issues may be discrete, success on one may improve the chances of success on another.” 

Overall, the chance was assessed as an 18% chance of success and Mr Chweidan was awarded 18% of the net value of his unlawful discrimination claim (which had initially been assessed at £586,059.09 gross) and received £64,363.47 plus interest.

Mrs Justice Simler said:

Although I have found that the chances of success were limited, there was more than a negligible prospect of the Claimant succeeding on appeal and having done so, proving his unlawful age discrimination claims.  In those circumstances, the breach of duty was the effective cause of these lost opportunities.  The Claimant is accordingly entitled to recover damages for the loss of opportunity suffered as a consequence of the Defendant’s breach.  I have assessed the loss of that opportunity as a loss of an 18% chance of overall success, either in the litigation or by achieving a settlement.

The principles to be applied

Mrs Justice Simler’s very clear analysis of the legal framework begins at paragraph 85 of her decision.  Having considered a number of the leading authorities, she condensed the legal principles in loss of chance cases into six propositions:

(i) The Claimant must prove that the claim had a real and substantial, rather than merely a negligible prospect of success.

(ii) If the court decides that the Claimant’s chances were more than merely negligible then it will have to evaluate them. That requires the court to make a realistic assessment of what would have been the Claimant’s prospects of success had the original litigation been fought out.

(iii) This means that the court should assess the likely level of damages which the Claimant would most probably have recovered had the underlying action proceeded to judgment and then apply an appropriate fraction to that sum to reflect the uncertainties of recovering such damages.

(iv) In some loss of a chance cases it may be appropriate to view the prospects on a fairly broad brush basis whilst in other cases it may be correct to look at the prospects in greater detail. In my judgment, whilst a broad brush approach is appropriate here the evidence and arguments in relation to the issues that would have arisen in the action have been canvassed extensively and clearly, enabling a more detailed approach than might otherwise be adopted.

(v) On the other hand the oral and documentary evidence available is more limited than what would have been available in the employment tribunal action and I have, obviously, not heard from witnesses who would have given evidence in that action. It is also possible that the claim might have settled. These features must be factored into any assessment and it would be wrong in any event, to conduct a trial within a trial or to make any firm findings in those circumstances as to what the EAT or an employment tribunal would have decided.

(vi) If there are “separate hurdles”, the percentage prospects on each should be multiplied together to give an overall lower percentage prospect.


It is not enough for a lawyer defending a professional negligence action to show that the claimant would not have succeeded in their underlying claim because they could not prove their case on the balance of probabilities; to successfully argue that breach of duty has caused no loss, it must be shown that the prospects of success were no more than negligible. 

In practice, a claimant with poor prospects of success in an underlying claim may have a better chance of recovering damages if their solicitor is negligent (through a claim for loss of a chance), than a claimant with better prospects of success and a non-negligent solicitor.


This content is provided free of charge for information purposes only. It does not constitute legal advice and should not be relied on as such. No responsibility for the accuracy and/or correctness of the information and commentary set out in the article, or for any consequences of relying on it, is assumed or accepted by any member of Chambers or by Chambers as a whole.


Please note that we do not give legal advice on individual cases which may relate to this content other than by way of formal instruction of a member of Gatehouse Chambers. However, if you have any other queries about this content please contact: