31 July 1970: the Royal Navy ends daily rum ration

Until the 17th century, sailors in the Royal Navy were given a daily beer ration of five pints, partly to compensate for the harsh physical demands of life on board, and partly because ordinary water quickly spoiled.

However, the growth in long-haul voyages made even beer impractical, so it was gradually replaced with a half-pint of the newly discovered rum. Rum's much higher alcoholic content (58%-95% versus 5%) meant it lasted longer, and far smaller quantities were needed to produce the same level of inebriation.

This kept morale up. It also meant sailors were frequently drunk. To preserve order on board, and ensure that sailors were fit for duty, punishments for outrageous drunkenness were severe, including public flogging with a braided rope known as the 'cat-o-nine tails' (only banned in 1879).

In 1913, the then First Lord of the Admiralty, Winston Churchill, famously said that the chief traditions of the Royal Navy were "rum, sodomy and the lash". Sailors who declined the ration were paid nine pence (roughly £3.63 in today's money).

Over time the ration was scaled back. In 1740 it was diluted to produce "grog", with the ration split into two servings. In the 19th century it was cut to the equivalent of a quarter of a pint (1823), then an eighth (1850). The reduction in physical labour and the need to be sober while operating complex machinery meant the "daily tot" was finally phased out in 1970.

Today, all Royal Navy sailors must be under the drink-driving limit while on duty, while some personnel (such as those operating weapons) are effectively banned from drinking alcohol.