Abstract
Justice must both be done and be seen to be done. A legal principle designed to give effect to this fundamental proposition is that a judge must not sit to determine a dispute if he or she is biased, or if there exists a reasonable perception that he or she is biased. Across many common law jurisdictions – including the UK, Australia, Canada, New Zealand and many jurisdictions in the United States – the judge in question himself or herself is required to undertake the assessment of whether bias, or an apprehension of bias, exists. Drawing on insights from behavioural psychology and a series of case studies from across these jurisdictions, this paper offers an extended analysis of this practice and identifies and evaluates alternative proposals.