The Tinbergen rule suggests that one instrument per objective is required, and so one instrument will be required per market failure, such as a tax to address an externality and labelling to address information failures (OECD, 2006, Tinbergen, 1952). In addition, as responses to environmental taxes change over time - behaviour change in the short term and changes in investment patterns and innovation in the medium and long term - packages of complementary instruments can facilitate these differentiated responses. Assuming that policies do not overlap, policy packages have the potential to act in a complementary way to achieve environmental goals while limiting compliance-cost uncertainty, enhancing enforcement possibilities and reducing administrative costs (OECD, 2006).