It is easy to think of the corroboration rules as a thing of the past – something which in a few years will no longer plague the law of evidence. Yet we must not forget the apparently intractable problem which they were designed to deal with – that of oath against oath, one person's word against another. Both historically and presently, the law has had to struggle with a choice between a regime of rules or a system of discretion; and the result is a fascinating compound of rule and discretion.