In recent decades, the UK has transformed its legal institutions in the name of reconciling national security powers with liberal human rights protections. This has been enacted in the name of enhancing UK Executive accountability and human rights protections in the national security domain. However, as this book argues, UK national security powers remain vulnerable to abuse and lack reliable human rights protections.

The book assesses the UK's turn away from largely secret Executive-made UK national security powers towards statutory law to regulate national security protection. The shift follows exposure of Executive abuse of self-regulated powers and the domestication of human rights requirements derived from the European Convention on Human Rights (ECHR). National security powers are now meant to be subject to democratic oversight, independent review and legal safeguards. Parliament has created expansive statutory national security powers based on Executive assurances they would comply with such requirements and, in many cases, be subject to robust judicial review. The result is a dramatic revision of the judicial role in the national security context, accompanied by a proliferation of specialist national security regimes, hybrid judge-led oversight bodies, as well as the spread of secret courts and other procedural innovations claimed to enable searching judicial scrutiny.

Blending theoretical, doctrinal, comparative and historical analysis, this book shows that UK judges are subjecting national security powers to more scrutiny than ever, and this has at times been rigorous. However, despite procedural innovations to enable factual scrutiny, the standard of review applied in national security cases tends to dissolve into rationality review. Moreover, judges are increasingly rejecting their role as principal national security safeguards, as assigned to them by Parliament. Instead, this book argues, many are returning to upholding a form of Executive sovereignty in the national security domain. With other oversight institutions currently ill-equipped to compensate for this, UK national security powers are increasingly free from constraints.