Arthur Herbert, 1st Earl of Torrington

It comes from the naval concept of fleet in being.

The first recorded use of the term was in 1690 by Admiral Arthur Herbert, 1st Earl of Torrington, commanding the Anglo-Dutch fleet in the Battle of Beachy Head.

With a superior French fleet, he believed maintaining a credible naval deterrent was enough to deter the threat of French invasion.

In the late 19th century Alfred Thayer Mahon, an American naval strategist, refined the concept to a defensive active posture, essentially a way for a weaker navy to tie down a stronger opponent without engagement.