In Scambler v HMRC, the Upper Tribunal sets out when it is permissible to look to the previous legislation to help interpret Tax Law Rewrite (TLR) statutes. There are only two ‘gateways’: real and substantial difficulty in interpreting the TLR provisions; and ambiguity which cannot be resolved by normal methods. These are narrower than the gateways to consider Hansard. ‘Ambiguity’ here has a precise meaning: where words are reasonably capable of bearing two or more distinct interpretations, rather than a single interpretation which might or might not apply because it has vague edges. It is also possible to go back to the original use of legislation in order to understand its context: Scambler does not affect that.