This book is my revised doctoral thesis submitted to the City University of Hong Kong in September 2016. It has been substantially revised and updated to include information regarding recent legal developments in both the United Kingdom (UK) and Hong Kong. In addition to the cases, other sources include scholarly commentaries and news coverage up to the time of publication. My collective research examines the extent to which the concept of proportionality has been integrated into the UK and Hong Kong, as well as what difficulties, either legal or political, the British and Hong Kong courts have encountered during this integration. This book also explores the possibility of the principle’s full adoption as a free-standing ground for judicial review litigation in these jurisdictions and its implementation as a basis for cases concerning socio-economic rights as enshrined in the International Covenant on Economic, Social, and Cultural Rights (ICESCR).

Proportionality was originally developed in Germany and has been made more prominent through European Union (EU) law and various international and regional human rights treaties, including the International Covenant on Civil and Political Rights (ICCPR), the ICESCR, and the European Convention on Human Rights (ECHR). My argument in this book is that ongoing developments in EU law and human rights law, as recognised by the Court of Justice of the European Union (CJEU) and the European Court of Human Rights (ECtHR), as well as developments in other common law jurisdictions (such as the United States, Canada, South Africa, and India), offer British and Hong Kong courts various opportunities to reassess their approaches to the integration of domestic standards. Debates concerning the constitutional role of the courts and the continuing institutional demands of EU law and human rights law have also raised questions about the potential benefits of such deeper integration. Although the viability of legal integration is often contested, I argue that full adoption of the proportionality principle would result in a more open approach to domestic adaptation.

In writing this book, I have incurred many debts, and would like to express my thanks, to various people. My research was supervised by Dr Mark Kielsgard, and I want to thank him for his advice and comment on my work. Moreover, Dr Kielsgard did not only provide me with the encouragement, support, and guidance necessary to complete this research, but has also shown his patience to read and comment on my last-minute submission, particularly as I was pursuing my doctoral degree on a part-time basis. I am indebted to his efforts and contributions. I would also like to thank the Viva Voce Examination Board Members, namely Professor Zhu Guobin, the Honourable Mr Justice Kemal Bokhary, GBM (Non-Permanent Judge of the Court of Final Appeal in the Hong Kong SAR and the Honorary Professor of the Faculty of Law, Chinese University of Hong Kong), and Dr Surya Deva (Associate Professor), for providing valuable comments to me when finalising the content of my thesis and this book. Furthermore, I would like to express my gratitude to my mother who has supported me throughout my research. I would also like to thank the editorial and design staff at City University of Hong Kong Press, who have helped me through the publishing process. Finally, this book is dedicated to the memory of my father, grandmother, uncle and aunt, my cousin Ms Ho Chui Ching, and my best friend Mr Chan Kwok Wai.