This is the second of two articles that empirically details the working practices of regulators charged with overseeing biological research. The first article considered how regulators from the Biological Agents Unit of the UK Health and Safety Executive went about implementing the British legislation controlling work with biological agents and genetically modified organisms prior to the terrorist attacks of 11 September 2001 and the ensuing anthrax letters in the U.S. This second article continues the investigation of the Biological Agents Unit's working practices by considering how its activities have changed and adapted to the new, post-9/11 policy and regulatory environment. The main argument put forward in the articles is that an understanding of the implementation processes--that is, the strategies adopted by regulatory agencies and the styles employed by agency regulators in their interactions with those regulated--is critical to developing a coherent policy logic for the emerging regulatory regime around biorisks.