"Tysabri", and "Perrigo" are words destined to become well known reference terms in the canon of Irish tax law, not so much on account only, of the Judgement this month in the High Court, on Perrigo’s €1.636bn tax case, but because it is destined to be adjudicated upon again, it seems likely, in the Supreme Court, and, in any case at the Tax Appeal Commission (TAC).