Tax investigations are rather like jungle expeditions—you never quite know what dangerous creatures you'll encounter, what traps await you, or whether you'll emerge with your dignity (and bank balance) intact. Having spent the better part of three decades navigating these treacherous waters, both as poacher and gamekeeper, Dr Clifford J. Frank can assure you that the landscape has become considerably more perilous in recent years.

When he first qualified as a tax adviser in the early 1990s, HMRC's predecessors operated with what one might charitably describe as a "gentleman's agreement" approach to tax compliance. A quiet word, a discreet adjustment, and everyone could return to their afternoon tea with honour intact. Those halcyon days are as extinct as the dodo.

Today's tax investigation is a sophisticated operation conducted by highly trained specialists armed with powers that would make a Victorian tax collector weep with envy. Schedule 36 of the Finance Act 2008, enhanced by subsequent legislation, has given HMRC the ability to peer into virtually every aspect of a taxpayer's financial life with the thoroughness of a Victorian housekeeper conducting a white-glove inspection……………