 The film also stars Matt Smith, Matthew Goode, Adam Bakri, Indira Varma, and Ralph Fiennes.The film had its world premiere at the Sundance Film Festival on 28 January 2019 and was released in the United States on 30 August 2019, by IFC Films, and in the United Kingdom on 18 October 2019, by Entertainment One.The true story of GCHQ employee Katharine Gun, who leaked a secret memo exposing an illegal spying operation by the United States of America, looking for information with which to gauge sentiment of and potentially blackmail United Nations diplomats tasked to vote on a resolution regarding the 2003 invasion of Iraq.