“ 15. Those requirements relate to the assessment process and are not relevant to the reasonableness of the enquiries, including the giving of a taxpayer notice, which HMRC may undertake. The information gathered as part of that process will be as apt to the question of assessment as it will be to the question of the underlying liability; both are encompassed within the expression “tax position” in Sch 36, para 1(1).”
“ 68. The purpose of the statutory scheme is to assist HMRC at the investigatory stage to obtain documents and information without providing an opportunity for those involved in potentially fraudulent or otherwise unlawful arrangements to delay or frustrate the investigation by lengthy or complex adversarial proceedings or otherwise. It is inevitable in many cases, particularly where there are complex arrangements designed to evade tax, that at the investigatory stage it will be difficult, if not impossible, for HMRC to be definitive as to the precise way in which particular documents will establish tax liability. It is also clear that in many cases disclosure of HMRC's emerging analysis and strategy and of sources of information to the taxpayer or those associated with the taxpayer may endanger the investigation by forewarning them.”