More for its novelty value, but (for Australians) also because it has a detailed discussion of the background to the causation provisions in the NSW Civil Liability Act 2002, you may be interested in the NSW CA decision in Zanner v Zanner [2010] NSWCA 343 (15 Dec 2010) http://www.austlii.edu.au/au/cases/nsw/NSWCA/2010/343.html . An 11 year old boy asked his mother if he could park the family car in the carport. She agreed, standing in front of it to guide him in... yes, you guessed- his foot slipped and hit the accelerator, and his mother was injured. Technically the action is by the mother against the son for damages (obviously to access the insurance policy). The Court of Appeal (Allsop P, Tobias & Young JJA) held that the boy did owe a duty of care as a driver; that while the standard of care was diminished due to his age, he was still negligent according to the standards of an 11 year old; and that his action had caused his mother's injuries. Clearly the mother was also at fault for allowing him to drive; but after an examination of the background to ss 5C and 5D of the CLA in the Ipp Report and articles by Professor Stapleton, the court concluded that causation was still made out. However, they ruled that the trial judge's verdict of 50% contributory negligence by the mother was too low, and raised it to 80%.

The only unfortunate feature of the judgement in my view is the passing comment by Allsop P at [11] that 

 "material contributions that have been taken to be causes in the past (notwithstanding failure to pass the ”but for” test) such as in Bonnington Castings Ltd v Wardlaw [1956] AC 613 are taken up by s 5D(2) which, though referring to “an exceptional case”, is to be assessed “in accordance with established principle”. "

Long term members will know this is a particular hobby-horse of mine. Bonnington does not deal with a case where a causal factor "failed to pass the but for test"! The smaller source of dust in that case was still a "but for", necessary condition for the disease to have occurred. This is quite different to Fairchild and Barker which are true exceptions to the "but for" rule, and have not so far been followed in Australia. One of the best pieces written on Bonnington in recent years clearly shows that it was a case where the ordinary "but for" rule applied- see  S H Bailey, “Causation in negligence: what is a material contribution?” (2010) 30/2 Legal Studies 167-185. See also the comments of the High Court in Amaca Pty Ltd v Ellis [2010] HCA 5 (3 March 2010) at [66]-[68].  

Regards

Neil