McLaren, a cheating Formula 1 team, got caught and fined £34M, so they deducted it from their taxes. The British tax authority objected, but they appealed, and won. Ren Reynolds has a gamerly perspective on this on Terra Nova:
In short McLaren argue that the fine was an expense related to the trade that they were engaged in. That there are exceptions to this such as statutory fines, but this was not such a fine, it arose out of the contract between them and the sporting body and it was not a 'punishment' but a commercial deterrent as such it was a risk of and thus an expense of trade.
The way that this has been presented in some elements of the UK media is a some what popularist version of the dissenting opinion in the case by Dee. This opinion holds that the fine was a punishment and that 'fines and penalties' of a similar nature are not allowable under tax law. What's more "the conduct of McLaren fell way outside any normal and acceptable way of conducting their trade, as found by the WMSC."
The problem with this view is that it misunderstands the nature of games / sport and in particular their relationship with law.
To put it simply the sort of conduct that is accepted as part of a gaming or sporting practice is not just that set out by the rules but also a wide set of acts that are within the tradition of the actual practice of that game or sport. That is, there are types of cheating that while outside the rules of the sport are still seen as being within the bounds of that sport.