The basis of this thesis is an investigation of Maritime and Coastguard Agency (MCA) administrative and criminal enforcement files, relating to UK detentions and prosecutions. It would appear that this is the first time that such an analysis has been made. The thesis is divided into four parts of which Part B and C form the heart of the work. These two consider administrative (Part B) and criminal (Part C) enforcement measures and discusses their legal basis. But before these subjects are dealt with in more detail, enforcement personnel and their roles are analysed (Part A), and their role is compared to inspectors of the Health and Safety Executive and the Marine Accident Investigation Branch (MAIB). Human rights and their impact on both enforcement process and inspectors of MCA and MAIB are addressed within the context of the Merchant Shipping Act 1995 and Regulations issued under the Act. The thesis identifies inconsistencies of UK legislation when compared with European law and apparent lack of clarification within UK law. The analysis of administrative enforcement measures focuses on detentions of merchant ships whereas the discussion of criminal enforcement measures concentrates on the areas which the files suggested were the most affected by investigations and prosecutions, namely groundings, violations of the Collision Regulations and pollution incidents. It becomes clear from the research that detentions by far outweigh prosecutions, that MCA policy supports this approach and that enforcement personnel indicate a preference for such administrative enforcement measures. However, a large number of Detention Notices were found non-compliant with legal requirements. Still only one case was identified, documented and discussed where the MCA was taken to arbitration by the owner affected by a detention. The thesis offers suggestions as to how the work of MCA enforcement personnel can be improved and (Part D) what measures would seem to be appropriate for the lawmakers to take in the future. It is suggested that the approach taken in recent European oil pollution legislation to focus on serious negligence rather than on strict criminal liability could offer a suitable way forward. Throughout this work I have endeavoured to state the law as at 31 October 2008. In a number of cases it has been possible to take account of developments since that date as my viva voce only took place in June 2009. I have made reference to new European and UK pollution legislation (see Chapter 13, fn 1) which came into force or will come into force in the course of 2009. I also used the decision in TS Lines Ltd v. Delphis NV (The TS Singapore), [2009] EWHC B4 (Comm) in Chapter 8.6.2. to help clarify the discussion about the quantum of compensation in an arbitration over a detention. But I did not carry out a detailed analysis of the new legislation and that case. The decision in Club Cruise Entertainment and Travelling Services Europe BV v. The Department For Transport [2008] EWHC 2794 (Comm) of 18 November 2008, however, was fully analysed and relevant aspects found their way into the discussion in the thesis.EThOS - Electronic Theses Online ServiceGBUnited Kingdo