David has considerable experience of advice and litigation in public international law. He has particular expertise on the UN Refugee Convention, the Council of Europe Convention on Action Against Trafficking in Human Beings, the UNECE Aarhus Convention on access to environmental justice, the UNECE Espoo Convention and the Kiev Protocol on environmental assessment in the transboundary context, as well as public international law issues arising out of their application and interpretation.
In addition, David has experience of the law of other commonwealth jurisdictions, most recently, the Turks and Caicos Islands (planning law) and Kenya (national security).
In the UK courts, David is regularly involved in cases raising issues of public international law, in particular in the national security field.
Amongst the recent significant cases in this area in which David has been involved are the following:
- Advising the Attorney General of the Turks and Caicos Islands on a possible appeal to the Turks and Caicos Court of Appeal against a decision of the Chief Justice declaring amendments to the Development Manual to be ultra vires.
- In the matter of the Northern Ireland Human Rights Commission  NIQB 96 – acted for the Commission, in its successful challenge to the legality of the prohibition on abortion in Northern Ireland in cases of rape, incest and serious foetal abnormality (led by Nathalie Lieven QC). The case involved detailed arguments on the Convention on the Elimination of All Forms of Discrimination against Women, the International Covenant on Civil and Political Rights, the United Nations Convention Against Torture and Other Cruel, Inhuman or Degrading Treatment and Punishment, the Council of Europe European Social Charter and Resolution 1607 (2008) and the United Nations Convention on the Rights of the Child, and the extent to which those Treaties could be relied on in the domestic courts.
- Lawrence, Nabil, Nasser v Attorney General – High Court civil damages action against the Attorney General alleging complicity in torture abroad by the security services (led by Lisa Giovannetti QC). The claim raises significant issues concerning foreign act of state and state immunity, and is currently stayed behind the leading case of Belhaj v Straw in the Supreme Court.
- R (Galdikas) v Secretary of State for the Home Department and Secretary of State for Work and Pensions – challenge to the application of the “genuine prospect of work test” to victims of trafficking. The case involves detailed arguments concerning the Council of Europe Convention on Trafficking and the extent to which it can be relied on in the domestic courts.
- Abdul v Secretary of State for the Home Department – leading case on Article 24(2) of the EU Charter of Fundamental Rights in the context of deportation and family splits.
- AM and BM (Trafficked women) Albania CG  UKUT 80 (IAC) – the case remains the leading examination of the domestic role in immigration cases of the Palermo Protocol on trafficking and the Council of European Convention on Trafficking.
In addition to practising in this field, David has also published on matters concerning international law. He is the author of the chapter on access to environmental information in Banner, The Aarhus Convention: A Guide for UK Lawyers (2015, Hart). He has lectured extensively in foreign jurisdictions on matters of international law, including international money laundering, fair trial rights, the right to liberty, human trafficking and terrorism. With Lord Slynn of Hadley, he delivered lectures to the senior judiciary of the Czech Republic and Zambia in 2003 and 2005. He delivered ECHR training on behalf of the Council of Europe to the judiciary in Turkey and Albania in 2006 and 2007.
David is ranked as a leading barrister by the legal directories. Chambers & Partners 2016 ranks him for administrative & public law, immigration and local government, describing him as "the young barrister of choice". The latest Legal 500 ranks David for administrative & public law, civil liberties & human rights and immigration. He "combines excellent judgement with solid all-round skills".