A segmented nut (100, 200, 300, 800, 900, 1000, 1100, 1710, 2300, 2510) for threaded engagement with a threaded shaft of a bolt, stud or rod, the segmented nut including an inner nut (102, 202, 302, 802, 902, 1002, 1102, 1202, 1302, 1402, 1502) and a sleeve (108, 208, 308, 808, 908, 1008, 1008, 1108, 1208, 1308, 1408, 1508, 1714, 1914, 2114, 2314, 2514) including a sleeve interface portion (112, 1212, 1312, 1412, 1512), characterised by: the inner nut including at least three segments (102a-c, 202a-c, 302a-c, 602a-c, 802a-c, 902a-c, 1002a-c, 1202a-c, 1302a-c, 1402a-c, 1502a-c, 1712a-c, 1912a-c, 2112a-c, 2312a-c, 2512a-c) providing at least a portion of a threaded aperture through the inner nut for engagement with the threaded shaft of the bolt, stud or rod, each of the at least three segments having at least one segment interface portion (106, 206, 806, 906, 1106, 1206, 1306, 1406, 1506), the sleeve engaging around and retaining together the at least three segments by engagement of the segment interface portions of the at least three segments of the inner nut with a respective part of the sleeve interface portion of the sleeve when the segmented nut is assembled such that the inner nut and the sleeve rotate together during threading of the segmented nut along the threaded shaft, at least a part of the respective segment interface portion of each of the at least three segments being at a greater distance from a central axis of the segmented nut than a minimum distance of at least part of the sleeve interface portion for the respective segment interface portion from the central axis, the at least one segment interface portion of each of the at least three segments and the respective part of the sleeve interface portion being in engagement with each other during at least part of release of the segmented nut, at least one segment of the inner nut being separable from contact with another segment of the inner nut when the segmented nut is moved into a released position, and at least one of the sleeve interface portion and the respective segment interface portion being configured to resiliently deform through contact of the sleeve interface portion and the respective segment interface portion during relative rotation of the sleeve and inner nut as the sleeve interface portion and the respective segment interface portion pass one another during release of the segmented nut. the inner nut including at least three segments (102a-c, 202a-c, 302a-c, 602a-c, 802a-c, 902a-c, 1002a-c, 1202a-c, 1302a-c, 1402a-c, 1502a-c, 1712a-c, 1912a-c, 2112a-c, 2312a-c, 2512a-c) providing at least a portion of a threaded aperture through the inner nut for engagement with the threaded shaft of the bolt, stud or rod, each of the at least three segments having at least one segment interface portion (106, 206, 806, 906, 1106, 1206, 1306, 1406, 1506), the sleeve engaging around and retaining together the at least three segments by engagement of the segment interface portions of the at least three segments of the inner nut with a respective part of the sleeve interface portion of the sleeve when the segmented nut is assembled such that the inner nut and the sleeve rotate together during threading of the segmented nut along the threaded shaft, at least a part of the respective segment interface portion of each of the at least three segments being at a greater distance from a central axis of the segmented nut than a minimum distance of at least part of the sleeve interface portion for the respective segment interface portion from the central axis, the at least one segment interface portion of each of the at least three segments and the respective part of the sleeve interface portion being in engagement with each other during at least part of release of the segmented nut, at least one segment of the inner nut being separable from contact with another segment of the inner nut when the segmented nut is moved into a released position, and at least one of the sleeve interface portion and the respective segment interface portion being configured to resiliently deform through contact of the sleeve interface portion and the respective segment interface portion during relative rotation of the sleeve and inner nut as the sleeve interface portion and the respective segment interface portion pass one another during release of the segmented nut.