Motor Crown Petroleum Ltd v SJ Berwin & Co (a firm) & Anor

In a professional-negligence claim, the court must distinguish causation from the assessment of loss. Causation is determined on the balance of probabilities. Where the defendant’s omission caused the claimant to lose an opportunity and the outcome depended on a third party, the claimant need not prove that the third party would probably have conferred the benefit. It is sufficient to establish a real or substantial, rather than negligible or speculative, chance. That chance is then valued as an assessment of damages.

Where damages are calculated by reference to the value of a developed asset, all costs required to obtain that value, including the acquisition cost, must be deducted.

The claimant acquired land for a proposed petrol filling station and instructed the defendants, solicitors, to conduct a planning appeal. The defendants failed to advise the claimant to challenge the emerging local plan before the statutory challenge period expired.

Longmore J found that the claimant would have brought a successful challenge and that a subsequent planning appeal had a 40 per cent chance of success. Damages were awarded on a lost-chance basis. The defendants appealed on causation, the assessment of the chance, and the deduction of the land acquisition cost.

1. Disposition. The appeal was allowed on the third ground only. The damages were reduced from £626,814.40 to £568,814.40, and interest was to be recalculated.
2. Causation and loss of chance. The court rejected the submission that the claimant had to prove, on the balance of probabilities, that the hypothetical planning appeal would have succeeded. Following Allied Maples Group Ltd v Simmons & Simmons (A Firm) [1995] 1 WLR 1602, the claimant had to prove on the balance of probabilities that it would have challenged the local plan and that the challenge would have succeeded. The resulting chance of success in the later planning appeal was a question of quantification. Since that chance was real or substantial and not negligible, it could be assessed as a percentage.
3. Distinction from causation cases. Hotson v East Berkshire Health Authority [1987] AC 750 required the court first to decide whether the issue was causation or quantification. Here, the defendants’ omission caused the loss of the opportunity to pursue the planning appeal in a materially different planning context. The 40 per cent assessment therefore represented valuation of the lost opportunity, not a finding that the defendants had failed to cause loss.
4. Assessment of the chance and reasons. The judge was entitled to make a broad evaluative assessment of the planning prospects. His reasons were sufficient, despite not analysing every expert opinion in detail. The assessment was not clearly wrong. The continuing relevance of Policy E1 did not make success negligible, particularly because the local plan inspector’s views could constitute a material consideration of substantial weight.
5. Damages. Because the claim was valued by reference to land with a constructed and operating petrol station, the £150,000 acquisition cost, as well as the £750,000 construction cost, had to be deducted from the developed value. The proper calculation was 40 per cent of the difference between £2,322,036 and £900,000.

• Court of Appeal (Civil Division): Allowed the appeal on the damages calculation only. The findings on causation, lost chance and the 40 per cent assessment were upheld.
• Queen’s Bench Division: Longmore J entered judgment for the claimant in damages of £626,814.40, together with consequential interest and costs orders.