[2] Jacob served as a commander of a company of Gentlemen Cadets at the Royal Military Academy, Woolwich until January 1931[3] and later at the Staff College, Camberley from 1931 to 1932, (where he passed the entrance examination with record marks), his fellow students there including Brian Horrocks, Sidney Kirkman, Frank Simpson, Cameron Nicholson, Arthur Dowler, Nevil Brownjohn, and Thomas Rees.

The departing head of the service, Sir Ivone Kirkpatrick (who would become the Chairman of the Independent Television Authority a decade later), recommended Jacob as a potential successor.

Sir William Haley, the BBC's Director-General, had already met Jacob during preparations to report the news of the D-Day landings and was aware that his political contacts (Churchill in particular) could be valuable.

In February 1950, he helped to establish the European Broadcasting Union (responsible for the Eurovision Song Contest and similar events) and served as its first President until 1960.

He immediately asked for William Haley to second Jacob from the BBC to reprise his advisory role, this time under the title of Chief Staff Officer.

After a single visit to the United States of America and Canada, Churchill realised that the Defence portfolio was relatively dull during peacetime; he left the post and appointed Field Marshal the Earl Alexander as his replacement.

Jacob was less comfortable working for Alexander than for Churchill, but a new opportunity arose for him in June 1952, when Haley announced he was to leave the BBC to become editor of The Times.

Indeed, the BBC's regional controllers informed the Chairman, Lord Simon of Wythenshawe, that they would resign simultaneously if Barnes was chosen over Jacob as Haley's replacement).

However, this goal led him to misinterpret the intentions of the controversial Editor of News, Tahu Hole, who was inclined to abuse the impartiality principle to avoid management responsibilities.

His former mentor Winston Churchill in particular had never liked the BBC's journalistic impartiality, thinking that broadcast media should be a tool of government rather than a forum of political analysis and criticism.

Though less radical (and certainly less well-known) than Greene, he saw the BBC successfully through many significant events in British broadcasting: the surge in television viewership (aided especially by the coverage of the Coronation of Queen Elizabeth II in 1953); the introduction of the competing ITV service in 1955; the gradual modernisation of some old eccentric practices (the aforementioned Fourteen-Day Rule and the Toddlers' Truce closedown period in the early evening).