AEU v Victoria  FCA 1196
Acts are presumed not to operate retrospectively7 – it’s all about fairness. Bromberg J explains (at [237-262]) that ‘retrospectivity’ has 2 senses – (A) changing legal rights concerning past events8, and (B) merely taking account of past events as the basis for how a future law will operate9.
The presumption applies only to type (A). It is rebutted by a contrary intention of ‘reasonable certainty’, which may be harder to show in tax contexts. iTip – get a feel for whether your situation is (A) or (B) – eg ‘Long-term leases made in 2010 are subject to tax from their commencement’ involves type (A). Next, see if text or context shows any contrary intention with ‘reasonable certainty’.
This case is from Episode 7 of interpretationNOW!
7 Palmer & Sampford (1994) 22 Federal Law Review 217.
8 Maxwell v Murphy (1957) 96 CLR 261 (at 285).
9 ADCO Constructions  HCA 18 (at ).