In the recent Lloyds TSB decision, the Court of Appeal overturned a tribunal decision allowing capital allowances in a leasing structure. It held that the tribunal’s approach to a ‘main object’ test appeared possibly flawed, and required the tribunal judges to reconsider their decision on the point. The leading judgment criticises the use of such tests in tax legislation. This article considers the case so far, and the problems with HMRC’s new-found enthusiasm for applying these tests. Discussion of this topic increasingly seems to involve loose references to rules of thumb. Taxpayers wishing to resist an HMRC challenge can do no better than to stick rigorously to the words of the legislation and published HMRC policy.