What is navy strength gin and what do you do with it?

Navy strength gin might seem like a high-alcohol oddity distilleries make just for a bit of variation. In reality, this style of gin comes from the deep seas of naval history and does more than just make your G&T a bit stronger.

Typically, you’ll find gin for sale at about 40%ABV. Navy strength must be at least 57%ABV, so it’s quite a bit stronger than your ordinary.

But why is it so much stronger? And why 57%?