Over the last few years, policies have been introduced in the UK which aim to improve organ transplantation rates by changing the way that potential organ donors are treated before death. Patients incapacitated due to catastrophic brain injury may now undergo ante-mortem donor optimisation procedures to facilitate deceased organ donation. As I identify in this thesis, the most significant ethical and legal problem with these policies is that they are not based on what the patient would have chosen for themselves in the specific circumstances. The policies identify and treat patients meeting certain clinical criteria as a group rather than the individuals, with their own viewpoints, that the law on best interests requires. They equate registration on the Organ Donation Register with ante-mortem donor optimisation procedures being in their best interests, despite registrants having neither been informed about nor given consent to ante-mortem interventions. The overarching claim I make in this thesis is that a system of specific advance consent is needed to provide a clear and unequivocal legal justification for ante-mortem donor optimisation procedures. The ethical foundation for this claim is autonomy, and this is the central theme running through all six chapters. I argue that autonomy should be incorporated into donor optimisation policy to promote the dignity and integrity of potential organ donors and to safeguard trust in the organ donation programme. I argue that a system of specific advance consent is needed as part of the duty of care owed to registrants on the Organ Donor Register and to facilitate the determination of the best interests of the potential organ donor. I argue that the state has not established the necessity of the current policy of non-consensual donor optimisation procedures and that they are under an ethical and legal obligation to introduce an autonomy-based framework for ante-mortem interventions to facilitate organ donation.