The role of international organisations in international law-making tends to be downplayed in this largely State-centric world. The practice of UNHCR, however, is reason enough for a more sophisticated appreciation of the role that operational entities can play in stimulating State practice, and of how they may interact with and guide domestic courts in treaty interpretation and application. The ILC's recently completed projects on customary international law and subsequent agreements and practice encourage a cautious approach, but the high degree of judicialisation in refugee decision-making, the strong legal content in the international protection regime and the impact of UNHCR's operational activities open the way for institutional and grass-roots developments, keeping the law in closer touch with social and political realities and with the needs of those displaced.

The interaction of international counter-terrorism laws with IHL is an area of renewed focus, amid widespread concern that the former are being (mis)applied to criminalise the provision of humanitarian assistance envisaged under the latter. The Security Council has begun to consider this issue in resolutions adopted in March and July 2019, but difficult questions of law and fact remain. These questions have significant practical consequences—for humanitarian agencies and those they seek to assist, as well as for States that must weigh different, and possibly conflicting, legal obligations. Much of the analysis to date and the solutions proposed, pay insufficient attention to the specifics of each legal regime.

The current relationship between UK and Strasbourg is politically fraught, which presents inevitable challenges for both jurisdictions. This article will analyse how the Strasbourg Court has responded to these challenges when dealing with applications against the UK, particularly when an application is brought following determination by the UK Supreme Court. It will be argued that there is some evidence that the Strasbourg Court has recently been using the admissibility stage as a novel site for effecting strategic behaviour, in order to moderate and influence UK–Strasbourg relations. The effect of this recent inclination, and some possible justifications for it, will then be set out.

The Syrian civil war has highlighted the phenomenon of foreign fighting, in which individuals leave their home State to join an armed conflict overseas. The predominant paradigm for regulating foreign fighting, centred on United Nations Security Council Resolution 2178, is based on counterterrorism, which in essence treats foreign fighting as a form of terrorism. This paradigm is largely reflective of the domestic legislation of the United Kingdom, United States, Canada and Australia. This article argues that this approach is problematic, and that an alternative paradigm based on the international law of neutrality and related domestic legislation provides a better means for regulating foreign fighting.

When bitcoin was released by the mysterious Satoshi Nakamoto in 2008, few could have predicted that it would attract as much attention as it has today. It has spawned a veritable host of other cryptocurrencies, including ether on the upstart Ethereum network, which boasts smart contract functionality. The underlying blockchain technology has also attracted attention, with some within the blockchain community suggesting that it can solve such diverse problems as secured digital voting to tracking food provenance. In the legal context, blockchains have been envisaged as capable of revolutionising registries for assets ranging from land to intellectual property, modernising clearing and settlement, and even fundamentally transforming the contracting process. This article critically evaluates the popular claims surrounding the potential of blockchain technologies to disrupt the legal system by separating hype from fact.

The relationship between EU citizenship and nationality is still defined by ‘linkage’ and ‘derivation’: national citizenship enjoys primacy over and conditions access to EU citizenship. However, because naturalisation decisions have a European dimension as well as a cross-border dimension, various commentators have questioned whether this primacy is desirable. This article examines alternative models of EU citizenship and argues that the answer is not to reconsider the criteria of ‘linkage’ and ‘derivation’, but to create some common EU rules on ‘access’ to national and EU citizenship. A particularly attractive solution is for rules on the grant of nationality to be guided by the idea of a ‘genuine link’. Reflecting on the Commission's recent report on investment citizenship within the EU and the debate it provoked, this article questions whether such shared rules can currently be adopted.

In its Chagos Advisory Opinion, the International Court of Justice (ICJ) ruled that the UK's detachment of the Chagos Archipelago from the colony of Mauritius on the eve of independence constituted a violation of customary international law (CIL). This article analyses the Court's approach to establishing the emergence and content of the right to self-determination in this frustrated case of decolonisation. It goes on to examine the argument that self-determination's peremptory character has decisive consequences in this specific context—a contention which found favour with several judges in their Separate Opinions. The article explores the extent to which the claims and counterclaims, made during the advisory proceedings, turned on countervailing readings of not only the key sources of custom but also of the principle of inter-temporal law. The final sections consider the significance of the Chagos Opinion for the Chagossians, both in relation to the Archipelago's resettlement and for their outstanding appeal in the UK courts (where the European Convention on Human Rights performs a pivotal role).

A key element of the right to self-determination is territorial integrity. This has usually been considered solely in relation to the territorial integrity of an existing State seeking to resist claims by peoples for the right to self-determination. Yet the Chagos Opinion by the International Court of Justice examines a different type of territorial integrity—that of the colonial territory itself. This article explores the consequence of the Court's view that the territorial integrity of the colonial territory is a matter of customary international law, and that any division, integration or other disruption of that colonial territory after December 1960 is unlawful, without the free and genuine consent of the people of the colonial territory. In particular this article seeks to explore what the Chagos Opinion means in terms of the territorial integrity of a colonial territory. It also examines the required conditions for ascertaining a free and genuine consent of the people of that territory, and the legal effects of not complying with them. There is also consideration of the implications for other situations from the clarification of customary international law in the Chagos Opinion, with a special focus on West Papua.

This article argues that the International Court of Justice's (ICJ) account of the customary law of environmental impact assessment (EIA) is incomplete. While acknowledging the role of the harm prevention principle in formulating the customary obligation to conduct EIAs, the ICJ has ignored the duty to cooperate, notwithstanding the latter duty's equally strong standing in international environmental law. Ignoring the duty to cooperate pushes the court towards a formal and sequential understanding of EIA, which undervalues the centrality of notice and consultation in EIA. In effect, viewed through the harm prevention lens alone, EIA is largely understood in instrumental and technical terms; whereas, if the duty to cooperate is brought back in, EIA's deliberative and ‘other-regarding’ nature is more clearly seen. This, in turn, recognises the normative and political role of EIA in structuring State interactions respecting environmental disputes.