In 2008, I was awarded a British Academy Small Research Grant worth Ł7409 to support a research project on the legal status of foreign armed forces under international law. The grant covered the employment of two postgraduate research assistants to help collect and analyze relevant primary materials. The grant also enabled me to spend some time at the Lauterpacht Centre for International Law in Cambridge as a Visiting Fellow. Although my visit was brief, it was all the more rewarding: the Lauterpacht Centre offers a wonderful setting for getting on with work and exchanging ideas with colleagues.

The grant has come to an end in July 2010. The materials collected during the course of the project provide strong evidence for two propositions. First, rules of customary international law do exist in this area which may be relied on to develop best practices and to promote greater transparency and accountability in relation to the legal status conferred upon visiting armed forces by States. Second, the legal position of visiting forces depends on the combined effect of several distinct areas or legal regimes of international law, including the law of State immunity and the law governing State jurisdiction, rather than a single legal regime. Both of these insights have significant practical and theoretical implications for international law which I intend to elaborate in my forthcoming monograph.