If you negligently produce a defective design, writes Kim Franklin, are you any less liable because someone else ought to have spotted the defect before it caused any damage? The purists among you will instantly recognise this exam question and rush to the case of Donoghue v Stevenson (1932).
In this case, recognised as the foundation of the modern law of negligence, the House of Lords found in favour of the claimant, because there was no opportunity to inspect the bottle of ginger beer before it was purchased - complete with a decomposing snail.
If you find these abstract questions of little interest, try this one: if you negligently design a warehouse roof with inadequate rainwater capacity, are you liable for the consequential ood damage to the contents - even if there had been an earlier ood in which the defect had been spotted but not communicated to the owners? Is the designer liable when it oods again?
If you find these questions difficult, it is because they are.
The law of tort constantly adapts to new and increasingly complex situations. At the same time, the courts want to define some universal guidelines rather than dealing with a string of tricky one-offs. In the recent case of Pearson Education Ltd v The Charter Partnership Ltd (CPL) (Judgment 21.02.07), the Court of Appeal's job was made harder by an earlier, remarkably similar case, which concluded with an answer they were not entirely happy with.
In the Pearson case, the defendant architect instructed specialist a subcontractor to design a siphonic rainwater drainage system with a ow rate of 75mm per hour. It should have been twice that.
The warehouse was leased to Pearson for storage of its books.
After a ood in 1994, its insurer instructed an investigation that revealed the defect, but it was never reported to the landlord.
Instead, it was understood that the ood had been caused by a rainstorm of 'exceptionally unusual intensity'. After a second ood occurred in 2002, the defect was remedied.
CPL admitted that it was potentially liable for the defect while it was latent, but that once it had been spotted it had ceased to be latent. On the basis of this, the first flood brought their liability to an end.
In the earlier case, Baxall & Norbain v Sheard (2002), the architect had instructed the same specialist to design a warehouse with a siphonic drainage system, which featured the same aw. There, the court found that because the defect ought to have been revealed by a purchaser's survey, the architect was not liable.
In the Pearson case the court considered this decision to be 'not wholly satisfactory' - it is one thing if an occupier discovers a defect but does nothing about it. A designer ought not to escape liability, however, if the claimant could have discovered the problem but did not do so. The court took the view that the architect was liable, and that nothing that occurred subsequently affected that liability.
Kim Franklin is a barrister and chartered arbitrator at Crown Office Chambers in London. Visit www.crownofficechambers. com