A useful case on the need for expert evidence in professional negligence cases. At page 549 Butler-Sloss L.J said,

In my judgment, it is clear, from both lines of authority to which I have referred, that a court should be slow to find a professionally qualified man guilty of a breach of his duty of skill and care towards a client (or third party), without evidence from those within the same profession as to the standard expected on the facts of the case and the failure of the professionally qualified man to measure up to that standard. It is not an absolute rule as Sachs L.J. indicated by his example but, less it is an obvious case, in the absence of the relevant expert evidence the claim will not be proved.

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