Editor’s Note: This is the text of the 2nd Annual British Embassy (The Hague) International Law Lecture, delivered on 23 May 2016 (part two of two). Part one is available here.
The relevance, engagement and application of international law in the domestic space are addressed explicitly and implicitly multiple times every day in the course of advice given to governments, advice that never sees the light of day and the issue in respect of which the advice is given only very seldom becoming the subject of litigation. In the course of such advice, it may be that the source of a legal obligation binding on the State assumes great importance. The issue may be, for example, whether the Government may be impleaded in this or that court or tribunal on the issue in question. The jurisdiction of the court or tribunal may thus bring with it questions about the relevant applicable law.
More often than not, though, the important question for consideration and advice is not the source of the obligation but rather its content. If compliance with the law, rather than defence against a claim of breach, is the issue, the source of the law is irrelevant. The State, or the Government, will be bound by relevant and applicable obligations of law whether they derive from national law or from international law.
Let me give you a tangible example. In 2009, the then UK Prime Minister, Gordon Brown, decided that the Government would produce what became known as Consolidated Guidance to Intelligence Officers and Service Personnel on the Detention and Interviewing of Detainees Overseas, and on the Passing and Receipt of Intelligence Relating to Detainees. This exercise emerged from the concern that there was no single, publicly disclosable document that set out how UK military personnel and intelligence officers were to proceed when engaging with foreign States on the question of the detention and interrogation of individuals held in foreign custody.