It is now 45 years since Australia decided to institute proceedings against France in the International Court in relation to atmospheric nuclear testing. Sir Elihu Lauterpacht QC was a key member of Australia’s legal team in the case. This reflection on the contribution to the case made by Sir Elihu draws on personal memories of the author, who was a junior member of the team, as well as archival material. It highlights the significant contribution made by Sir Elihu in terms of his advocacy and ideas as to legal strategy in relation to the case. This contribution so impressed that he was appointed Legal Adviser to the Australian Department of Foreign Affairs in 1975.