HMRC's Management of the UK Tax System: The Boundaries of Legitimate Discretion

To operate efficiently and effectively revenue authorities require discretion, but processes must be in place to keep discretion in check. This delicate balancing act takes place against the background of a more general constitutional framework. This working paper starts by outlining the unique features of the UK constitution that form the background to the way in which the discretion of the UK revenue authorities (HMRC) is assessed and controlled. It then discusses a limited, yet crucial, set of discretions vested in HMRC. The paper focuses particularly on the use of non-statutory guidance. It discusses the operation of judicial review, and in particular, the doctrine of legitimate expectations, in the context of such guidance. It then presents two case studies, which reveal a distinct uncertainty over the limits of non- statutory guidance. This is currently of considerable concern to the UK tax community. As the role of guidance appears to be increasing in the UK system, the case for addressing some of these causes of uncertainty strengthens. The paper concludes by offering some preliminary suggestions on how the problems may be addressed