In Jones v Secretary of State for Energy and Climate Change36 the High Court considered the issue of common costs37 in industrial disease group litigation where the lead claimants were successful in respect of a proportion of the issues in dispute but not in respect of others. While the decision turns on its facts, it provides a useful illustration of the approach which the courts may adopt in factually complex group litigation where identifying the successful party, and the extent to which that party has been successful, is not straightforward, and gives guidance on the issues which may be taken into consideration. The parties in Jones agreed that the order for costs should not be issue based but that any deduction should be expressed by reference to a percentage. After careful analysis of the issues raised during the course of the litigation Swift J held that it would be appropriate to award the claimants 80% of their costs, on the basis that they had been the successful party at trial but had failed to establish a causative link for two types of cancer (which had required separate investigation and evidence and had occupied a significant proportion of the technical and medical evidence). Interestingly, the defendants were not penalised for their failure to make Part 36 offers as it was recognised by the court that there are significant practical problems in making appropriate offers in group litigation of this nature.