The United Kingdom has a long-standing rum culture, particularly thanks to the many Caribbean islands and rum-producing countries that made up the Commonwealth.
Rum is deeply rooted in British culture, once being the drink of choice for sailors. Indeed, sailors of the British Royal Navy were entitled to a daily ration of rum called "Tot of rum".
This is where the term “Navy Proof” comes from. The story goes, that sailors poured the rum over gunpowder and set it on fire, to "prove" that the rum was at the correct alcohol content and had not been reduced with water. There are several brands such as Blacktot or Lamb's.