Penelope has a broad public international law practice, which combines traditional interstate cases with investment treaty arbitration and domestic litigation and advice work. Her practice encompasses investment treaty arbitration, law of the sea, law of territory, recognition, environment and wildlife law, sanctions (EU, UN and national), treaty law, human rights, corporate social responsibility (OECD Guidelines and Ruggie Principles), international and regional organisations, jurisdiction and immunities, public law and EU law. She also has considerable knowledge of international humanitarian law and the use of force and has worked on territorial sovereignty and delimitation disputes.
Penelope has particular expertise in dealing with the complex interface between public international law, EU law and domestic law, and how law and 'soft law' from one legal system is implemented, interpreted and applied in another. She is on the Attorney-General's Specialist Public International Law "B Panel", and the general "C Panel". She is an experienced practitioner, starting her career as a litigation lawyer at leading New Zealand law fim, Chapman Tripp, in 1997 before working moving to academia following her LLM (2001-02), and the Bar in 2010.
Penelope is a Senior Research Fellow and Affiliated Lecturer at the Transnational Law Institute, King's College London, where she lecture on undergraduate and post-graduate courses. She is also a visiting lecturer at the University of Auckland and the University of Cambridge, having previously been a College Lecturer and Fellow at Downing College and the Lauterpacht Centre for International Law.
Current and recent cases include:
- Acting for the Home Office in a judicial review action concerning the Refugee Convention and the Sovereign Base Areas of Dhekelia and Akrotiri, Bashir v Secretary of State for the Home Office  EWHC 954 (Admin) (tbr)
- Acting for the FCO in an Employment Tribunal claim arising out of a secondment to EULEX in Kosovo, Bamieh v EULEX Kosovo and Ors, Decision on Preliminary Issues, 15 April 2016
- Advising the Marine Management Organisation on various issues, including implementation of marine licensing exemptions and the relationship of UNCLOS with the licensing of marine activities concerning underwater cultural heritage
- Working with claimants in several ongoing investment treaty arbitrations
- Advising on potential proceedings under the UN Law of the Sea Convention concerning an arrested vessel
- Judicial review claim in R (Bancoult) v Secretary of State for Foreign and Commonwealth Affairs, successfully defending the challenge to the declaration of the large-scale BIOT Marine Protected Area in the Admin Court and Court of Appeal and in the application to appeal to the Supreme Court
- Successfully making a damages claim against charterers/owners in arbitration arising out of a refusal to comply with a voyage order to a north Cyprus port
- Acting for the United Kingdom in Mauritius v UK, an Annex VII arbitration under the Law of the Sea Convention, raising Mauritius's claim to sovereignty over the British Indian Ocean Territory and its challenge to the large-scale BIOT Marine Protected Area and advising on subsequent related matters.