Les Laboratoires Servier and another v Apotex Inc and others [2012] EWCA Civ 593; [2012] WLR (D) 138

“The court was able to take into account a wide range of considerations in order to ensure that the ex turpi causa defence only applied where it was a just and proportionate response to the illegality in question. Although a party claiming compensation on a cross-undertaking in damages for lost sales of products the manufacture of which infringed a foreign patent was relying on an unlawful act sufficiently causative of its claim to engage the defence in principle, the defence did not apply where the party had believed reasonably and in good faith that the patent was invalid, and the illegality was recognised by making a deduction in the assessment of damages for the amount which the foreign court would have awarded in patent infringement proceedings.”

WLR Daily, 3rd May 2012

Source: www.iclr.co.uk