Key joined the
Royal Navy in 1984. After serving as an observer in the
Fleet Air Arm, he saw action as a Principal Warfare Officer in the
frigate during the
Kosovo War in 1999. he was appointed a staff officer at the
Permanent Joint Headquarters in Northwood in 2007. Key was appointed Principal Staff Officer to the
Chief of the Defence Staff in November 2011, and
Flag Officer Sea Training in April 2013. He was appointed
Fleet Commander and promoted to the rank of
vice admiral on 10 February 2016. He became
Chief of Joint Operations in April 2019. Key received the United States
Bronze Star Medal in 2006 and was appointed
Commander of the Order of the British Empire (CBE) in the
2016 New Year Honours, and
Knight Commander of the Order of the Bath (KCB) in the
2021 New Year Honours. He was awarded the
Honorary degree of
Doctor of Science (D.Sc) by
Royal Holloway, University of London on 20 December 2018. Key led
Operation Pitting, the UK's evacuation efforts in Afghanistan following the
2021 Taliban offensive, in August 2021 and, on 15 October, it was announced that Key was to be the next
First Sea Lord. He assumed the post from Admiral
Sir Tony Radakin on 8 November 2021. On 2 July 2025, the Ministry of Defence announced that, following the investigation, Key's Royal Navy service and commission had been terminated. The BBC reported that Key had violated the military's code of conduct by having an affair with a more junior female officer. ==Personal life==