Originating with the Royal Navy, the executive curl, or alternatively the "Elliot's Eye", is the name given to the ring above a naval officer's gold lace or braid insignia.
The precise origin of "Elliot's eye" is somewhat of a mystery. One story is that it is in memory of Captain George Elliot (1813–1901), who, when wounded in the arm in the Crimean War, used the gold on his sleeve as a sling. There are also theories that the Elliott’s eye refers to the method of making an eye in a hemp cable and is said to have been introduced into the Service by the Honourable William Elliot, a member of the Board of Admiralty in 1800 and 1801.
Lord Anson’s Board of Admiralty issued the first uniform regulations in 1748 in order to set a distinction between naval and other officers, and lay down precise rules of rank and precedence among naval officers. Distinctive lace on the sleeves of flag officers was introduced in 1783 and was extended to other officers in 1856 with the addition of the curl in the uppermost row of lace for officers of the executive branch only. From 1879 to 1891 Royal Navy officers wore three brass buttons between the lace. In January 1915, the use of the curl was extended to engineer officers and to other officers in 1918. The naval pattern lace was different in that it followed a straight line with a round loop while British Army uniforms were decorated on the sleeve with a loop that rose to a peak in the form of a “crow’s foot” or “Austrian knot”.
When the Royal Naval Reserve was formed in 1859 its officers were differentiated from regular officers with rank braid that was half the width and formed two waved lines, one superimposed upon the other with a six-pointed star in place of the curl.
In 1903 the Royal Naval Volunteer Reserve was instituted and the officers were distinguished with waved stripes worn parallel to each other, surmounted by a squared waved “curl”.
Officers of the Women’s Royal Naval Service wore sky-blue lace with a diamond-shaped loop.
Although in the Royal Navy the curl is now common to all officers (less those of its associated cadet forces), some other navies who copied the custom have restricted its use to their deck officers. While some navies placed insignia above the braid to indicate specialist branches, Commonwealth navies used coloured cloth beneath the gold lace. Coloured branch distinction, first introduced in 1863, went out of use except for the medical, nursing, medical administration and technical branches, on 31 December 1959.