The rule of practice that requires judges to direct juries that it is dangerous to act on the uncorroborated evidence of certain categories of witness, namely accomplices, the alleged victims of sexual offences and children, has been diluted in certain jurisdictions, and subjected to rigorous criticism by a number of academic commentators. In this article it is proposed to consider whether a mandatory corroboration warning can ever be justified in respect of a particular category of witness. Rather than consider in detail the arguments in favour of retaining the warning for each of the present categories of witness, it is proposed to examine the case for the very idea of a corroboration warning in respect of any category of witness. We shall approach this question by first considering what it is that a corroboration warning requires a jury to do, over and above their ordinary task of determining the credibility of the evidence against the accused and deciding whether the accused is guilty beyond reasonable doubt. Attention has focused on the “enormous superstructure” that has been erected on the basic proposition that the evidence of some witnesses should be approached with caution and on the heavy burden that this imposes on a trial judge summing up to the jury. But another matter to consider is the demands that a corroboration warning imposes on the jury and whether it can ever be justified to make these demands in respect of particular categories of witness.