She was completed as Alert, an Admiralty Yacht for command and gunboat diplomacy duties in the Mediterranean and Far Eastern stations.

[2] Alert was commissioned for service on 24 October 1946, and arrived at Singapore, her home port, on 29 November, to join the British Pacific Fleet.

[3] In late 1951 Alert was temporarily deployed with United Nations Task Group to carry out naval fire support operations off the west coast of Korea.

[3] In October 1952 she sailed to the north-west coast of Western Australia to take part in "Operation Hurricane", the first British atom bomb test.

Later, in April 1957 she sailed to Christmas Island as part of "Operation Grapple", Britain's first thermonuclear bomb tests.