Concern about the width of tax authority powers and their effects on taxpayers is hardly confined to the UK or to modern times. Indeed, the relationship between the public imperatives of taxation (including revenue-raising, regulation and redistribution) and the private interests of taxpayers has long been deeply contentious not only in practical tax administration but also in constitutional and philosophical debates about taxation. Nevertheless, there is something distinctively worrying about the recent UK practice in which new statutory powers are conferred on HM Revenue & Customs (HMRC) in each annual Finance Bill, possibly as a way of demonstrating the government’s seriousness of purpose in tackling tax avoidance rather than because the powers are genuinely needed, and certainly without a consistent vision of what powers ought and ought not to be possessed by a tax authority. A number of investigations have been carried out by Parliamentary committees, research institutions and HMRC itself with a view to rationalising or at least reorganising HMRC’s powers, but these are typically overtaken by the conferral of even more powers. They have, in any case, not fully succeeded in fostering a culture of greater deliberation about how best to equip HMRC in carrying out its statutory functions of raising and managing taxes.