International law applies to cyber operations – but views differ on exactly how. Does state-sponsored interference in another state's affairs using cyber means – for example, disinformation campaigns in elections, disabling government websites, or disrupting transport systems – breach international law? If so, on what basis, and how are the principles of sovereignty and non-intervention relevant? States are increasingly attributing cyber operations to other states and engaging in the debate on how international law applies, including circumstances that would justify countermeasures.

As states meet to debate these issues at the UN next month, Harriet will explore how international law regulates cyberoperations by states, and consider the prospects of progress at the UN and through other initiatives. 

Harriet Moynihan has been an associate fellow in the International Law programme since 2015, and has worked on international law issues in a number of capacities, including as an academic, a government legal adviser, and in private practice.

As a legal adviser in the UK Foreign and Commonwealth Office, Harriet advised on a wide range of public international law issues, including representing the UK in the Council of Europe, before the European Court of Human Rights, and in negotiations on bilateral and multilateral agreements.Harriet’s work currently focuses on the application of international law to new technology including cyber operations, and on China’s approach to the international legal order.

Harriet also advises on state responsibility, international humanitarian law and international human rights law issues in a variety of contexts, including the use of armed drones.

Harriet regularly chairs events at Chatham House and elsewhere, and lectures on international law as part of the Queen Elizabeth Academy Leadership Programme. She has also lectured on international humanitarian law as part of Oxford University’s Diplomatic Studies Programme. She is currently a research visitor at the Bonavero Institute of Human Rights, University of Oxford, and a visiting fellow of Mansfield College, Oxford.


The PIL Discussion Group hosts a weekly speaker event and light lunch and is a key focal point for PIL@Oxford. Topics involve contemporary and challenging issues in international law. Speakers include distinguished international law practitioners, academics, and legal advisers from around the world.
The group typically meets each Thursday during Oxford terms in The Old Library, All Souls College, with lunch commencing at 12:30. The speaker will commence at 12:45 and speak for about forty minutes, allowing about twenty five minutes for questions and discussion. The meeting should conclude before 2:00. Practitioners, academics and students from within and outside the University of Oxford are all welcome. No RSVP is necessary. Join the PIL Email List to receive information about the PIL Discussion Group meetings, as well as other PIL@Oxford news.
To join the Public International Law Discussion Group email list, which offers details of all events and other relevant information, send a message to: . (You do not need to write any text in the body of the message, or even put anything in the Subject: line unless your mailer insists on it.) You will be sent a confirmation request, and once you reply to that, a message confirming your subscription will follow. Alternatively, you can send an email to Jenny Hassan to be added to the PIL mailing list.
Convenors of the Oxford Public International Law Discussion Group are: Eirini Fasia and Hannes Jöbstl.

The discussion group's meetings are part of the programme of the British Branch of the International Law Association and are supported by the Law Faculty and Oxford University Press.