Having sufficient quality capacity within a given jurisdiction is clearly important to ensure SEA can be delivered effectively and there is a broad trend internationally within environmental assessment toward formally regulating the capacity of key actors. Internationally, certification schemes have been introduced for EIA practitioners in a number of jurisdictions. It is our experience, however, that national certification schemes have often proven problematic in practice. In comparison, there is some evidence to suggest that the more market-driven accreditation processes operating in the UK have had some positive effects. So does regulation work? And what types of regulation work?