A tubular structure comprising: an elongate tubular member extending between a first end and a second end , wherein the tubular member comprises an inwardly tapered portion adjacent said first end , the inwardly tapered portion narrowing the tubular member in a longitudinal direction towards said first end ; and a nut provided internally of said tubular member at said inwardly tapered portion , said nut having an outer surface that is in contact with an inner surface of said tubular member ; and an annular member provided externally of said tubular member at said inwardly tapered portion , said annular member having an inner surface that is in contact with said outer surface of said tapered portion ; and wherein: the inner surface of said tubular member at said inwardly tapered portion is tapered so as to extend at an angle that compliments an angle of the outer surface of said nut , and wherein said outer surface of said tubular member is tapered so as to extend at an angle that compliments an angle of said inner surface of said annular member ; characterized in that at least one channel is provided that extends from said outer surface of said annular member , through both of said annular member and said tubular member and at least partially into said nut , and in that a securing member is provided within said channel so as to extend from said external surface of said annular member , through said tubular member and at least partially into said nut . an elongate tubular member extending between a first end and a second end , wherein the tubular member comprises an inwardly tapered portion adjacent said first end , the inwardly tapered portion narrowing the tubular member in a longitudinal direction towards said first end ; and a nut provided internally of said tubular member at said inwardly tapered portion , said nut having an outer surface that is in contact with an inner surface of said tubular member ; and an annular member provided externally of said tubular member at said inwardly tapered portion , said annular member having an inner surface that is in contact with said outer surface of said tapered portion ; and wherein: the inner surface of said tubular member at said inwardly tapered portion is tapered so as to extend at an angle that compliments an angle of the outer surface of said nut , and wherein said outer surface of said tubular member is tapered so as to extend at an angle that compliments an angle of said inner surface of said annular member ; characterized in that at least one channel is provided that extends from said outer surface of said annular member , through both of said annular member and said tubular member and at least partially into said nut , and in that a securing member is provided within said channel so as to extend from said external surface of said annular member , through said tubular member and at least partially into said nut . the inner surface of said tubular member at said inwardly tapered portion is tapered so as to extend at an angle that compliments an angle of the outer surface of said nut , and wherein said outer surface of said tubular member is tapered so as to extend at an angle that compliments an angle of said inner surface of said annular member ; characterized in that at least one channel is provided that extends from said outer surface of said annular member , through both of said annular member and said tubular member and at least partially into said nut , and in that a securing member is provided within said channel so as to extend from said external surface of said annular member , through said tubular member and at least partially into said nut . <EOS>