A pipe coupling which includes: • a male portion which in use is rigidly secured to one end of a first pipe, coaxial with said first pipe; • a female portion which in use is rigidly secured to one end of a second pipe, coaxial with said second pipe; • the male and female portions (13,14) being sized so that the male portion is an easy sliding fit within the female portion when the first and second pipes (10,11) are connected together; • the male portion being provided with a series of spaced keys protruding from the outer surface thereof; • the female portion being provided with a series of spaced keyways which are dimensioned and arranged so that the keys are a sliding fit within the keyways when the male and female portions (13,14) are connected together; • at least one fastener, each of the at least one fastener including: • a male portion fitting rigidly secured to, or formed in, the male portion and providing at least one internally screw-threaded bore; • a female portion socket (22,22a) rigidly attached to, or formed into, the female portion, said female portion socket (22,22a) including a central aperture which is shaped to receive a plug (24,24a) therein, said female portion socket (22,22a) and said plug (24,24a) being radiused to match the radius of the female portion, and being substantially rectangular in plan; • a securing bolt dimensioned to fit in a corresponding fixing aperture formed in said plug (24,24a), said securing bolt being releasably engageable with a corresponding bore; and • the male portion fitting is shaped, at least in part, to receive a portion of the plug (24,24a); wherein said plug (24,24a) is sized relative to the female portion socket (22,22a) such that the plug (24,24a) has a predetermined amount of movement relative to the female portion socket (22,22a) in either direction around the circumference of the female portion, even when each securing bolt present is engaged with the corresponding bore. • a male portion which in use is rigidly secured to one end of a first pipe, coaxial with said first pipe; • a female portion which in use is rigidly secured to one end of a second pipe, coaxial with said second pipe; • the male and female portions (13,14) being sized so that the male portion is an easy sliding fit within the female portion when the first and second pipes (10,11) are connected together; • the male portion being provided with a series of spaced keys protruding from the outer surface thereof; • the female portion being provided with a series of spaced keyways which are dimensioned and arranged so that the keys are a sliding fit within the keyways when the male and female portions (13,14) are connected together; • at least one fastener, each of the at least one fastener including: • a male portion fitting rigidly secured to, or formed in, the male portion and providing at least one internally screw-threaded bore; • a female portion socket (22,22a) rigidly attached to, or formed into, the female portion, said female portion socket (22,22a) including a central aperture which is shaped to receive a plug (24,24a) therein, said female portion socket (22,22a) and said plug (24,24a) being radiused to match the radius of the female portion, and being substantially rectangular in plan; • a securing bolt dimensioned to fit in a corresponding fixing aperture formed in said plug (24,24a), said securing bolt being releasably engageable with a corresponding bore; and • the male portion fitting is shaped, at least in part, to receive a portion of the plug (24,24a);