Byers was involved in the 1998–1999 extradition case concerning former Chilean military ruler Augusto Pinochet in the British House of Lords, working with Ian Brownlie QC and members of a legal team representing Amnesty International and other human rights organizations. One of Byers' roles was to speak with the British and international media. He also wrote about the Pinochet case in the "Times of London", the "London Review of Books", the "British Yearbook of International Law", and the "Duke Journal of Comparative and International Law".