In order to ensure that purveyors of spirits were selling high quality products, an apocryphal tale suggests that the British Royal Navy would measure a spirits’ strength by igniting it. So when the spirits and gunpowder (stored in the same cargo hold) were accidentally spilled upon one another, the gunpowder was still usable (to say nothing of the spirit, which was presumably no longer drinkable)
Anyway, the term “Navy Strength Gin” is a 1990s marketing creation to sell spirits which meet 100° UK Proof (114 modern proof), and are 57.1% ABV. The romantic and evocative term has stuck and today, high proof gins are often bottled at 57.1 ABV, though in our reviews we consider anything in this range or higher to be Navy Strength.
Navy Strength Gins are fantastic for cocktails as they maintain their gin character even in small quantities.