 Promoted full admiral on 8 March 1963, on appointment as Commander-in-Chief of Far East Command and British military adviser to the South East Asia Treaty Organization, at a time of when President Sukarno of Indonesia was stepping up pressure on Malaysia.Advanced to Knight Grand Cross of the Order of the Bath in the 1965 Birthday Honours and appointed an honorary Commander of the Malaysian Order of the Defender of the Realm, he went on to be Commander-in-Chief, Portsmouth in August 1965.Begg was appointed First Sea Lord and Chief of the Naval Staff, following the sudden resignation of his predecessor Sir David Luce, in March 1966.