In what year did the Royal Navy abolish the tradition of the daily rum ration?

The rum ration (also called tot) was a daily amount of rum given to sailors on Royal Navy ships. The abolition of the rum ration had been discussed in Parliament in 1850 and again in 1881 however nothing came of it. In 1970, Admiral Peter Hill-Norton abolished the rum ration as he felt it could have led to sailors failing a breathalyser test and being less capable to manage complex machinery.

The practice of compulsorily diluting rum in the proportion of half a pint to one quart of water (1:4) was first introduced in the 1740s by Admiral Edward Vernon (known as Old Grog, because of his habitual grogram cloak).

The rum ration consisted of one-eighth of an imperial pint (70 mL) of rum at 95.5 proof (54.6% ABV), given out to every sailor at midday. Senior Ratings (Petty Officers and above) received their rum neat, whilst for Junior Ratings it was diluted with two parts of water to make three-eighths of an imperial pint (210 mL) of grog. The rum ration was served from one particular barrel, also known as the "Rum Tub", which was ornately decorated and was made of oak, reinforced with brass bands, with brass letters saying, "The King, God Bless Him" or "The Queen, God Bless Her".