Dr Kate Parlett > Twenty Essex > London, England > Barrister Profile

Twenty Essex

Work Department


Kate specialises in public international law and international arbitration. Her practice covers the full range of public international law including land and maritime boundaries, law of the sea, state responsibility, treaty obligations, immunities, the use of force, international humanitarian law, international trade law, human rights, environmental law and sanctions. She also represents states and investors in investment treaty arbitrations, including under the ICSID and UNCITRAL rules.

Kate has extensive experience as an advocate before international tribunals and domestic courts. Kate has been instructed and appeared before the International Court of Justice (ICJ) in disputes concerning land and maritime boundaries, transboundary environmental harm, and treaty and other international obligations. She has also been instructed in several cases before the European Court of Human Rights. She has recently appeared before the English courts in numerous leading cases involving diplomatic immunity, head of government immunity, and Foreign Act of State.

She also sits as arbitrator in international commercial disputes across a range of sectors and institutional rules. Kate holds Australian nationality only.

Kate is recommended as a leading junior for public international law in the legal directories. She has been most recently described as having a ‘first rate intellect, very well-organised mind, very diligent and able to get on with whatever the task – including complex factual and expert issues.’

Kate has taught public international law, international investment and commercial arbitration, and international human rights law at the universities of Cambridge, Paris-II (Panthéon-Assas), Queen Mary (University of London), Queen’s University (Canada), Queensland and at the Graduate Institute in Geneva.



French (conversational)

Lawyer Rankings

London Bar > Public international law

(Leading Juniors)Ranked: Tier 1

Kate ParlettTwenty Essex ‘She is fantastic, excellent strategic and pragmatic mind. She has is a legal heavyweight, with the ability to deliver on a human and sensitive level that clients can understand and brilliant drafting skills.’

Twenty Essex ‘is excellent on public international law, with a very deep bench of specialists at all levels of seniority’ and has bolstered its offering with Baiju Vasani and Rishab Gupta joining in May and November 2022, respectively, as well as several silk appointments including Sir Michael Wood KCMG KC’s appointment to honorary silk in March 2023. Members of chambers are acting at the forefront of groundbreaking matters at the highest level across the whole range of public international law. Highlights include the UK’s intervention on behalf of Ukraine in its claim against Russia before the ICJ based on allegations of genocide, in which Philippa Webb is instructed on; Kate Parlett is instructed on Australia’s intervention. In UN human rights committee proceedings Torres Strait Islanders v Australia, Monica Feria-Tinta and Sudhanshu Swaroop KC acted on behalf of a group of Torres Strait Islanders, indigenous people resident on an archipelago off the coast of mainland Queensland, who argue that Australia’s policies and laws regarding climate change are in breach of the International Covenant on Civil and Political Rights.


London Bar > International arbitration: arbitrators

Twenty Essex is ‘a very strong set in the international arbitration arena with many outstanding arbitrators’ such as Sir Bernard Rix, Sara Masters KC, and Duncan Matthews KC. Appointments span all major arbitral institutions including ad-hoc arbitrations under the UNCITRAL rules across many sectors including energy, insurance, mining, IP, pharmaceuticals and a wide range of commercial disputes. While the set continues to be globally recognised and respected for its strong commercial expertise, its reputation for investor-state work grows with regular investor-state arbitration appointments. Notable additions boosting the set’s bench strength include Baiju Vasani, Wendy Miles KC, both also acting as counsel, and Philippa Charles, who joined from Stewarts Law LLP. Clare Ambrose is particularly sought-after as a full member of the LMAA and Sir Peter Gross attracts appointments in maritime as well as commercial disputes. Kate Parlett is building a strong practice of high-value international commercial arbitration appointments.