A cutting insert comprising: opposing upper and lower surfaces (12D, 12E), opposing longitudinal side surfaces and opposing lateral side surfaces extending transversely to and connecting the opposing longitudinal side surfaces; a cutting insert through bore passing between the opposing upper and lower surfaces (12D, 12E); opposing first and second longitudinal walls (12F, 12G) extending between the upper and lower surfaces (12D, 12E) and between a portion of each of the longitudinal side surfaces and the through bore; and opposing first and second transverse walls (12H, 12I) extending between the opposing upper and lower surfaces (12D, 12E), and extending transverse, and connected, to the opposing first and second longitudinal walls (12F, 12G); wherein: the cutting insert through bore is bounded by inner surfaces (12F1, 12G1, 12H2, 1212) of the opposing first and second longitudinal walls (12F, 12G) and of the opposing first and second transverse walls (12H, 12I); and each of the inner surfaces (12F1, 12G1) of the first and second longitudinal walls (12F, 12G) is formed with a protruding clamping lip (12F2, 12G2) which projects into the through bore, wherein each protruding clamping lip (12F2, 12G2) is spaced from the upper surface; characterized in that the cutting insert is elongated with a longitudinal cutting insert axis ( A H) extending through the center thereof via first and second ends (12A, 12B); the cutting insert through bore has an elongated shape in a plan view of the upper surface; and each inner surface (12H2, 12I2) of the first and second transverse walls (12H, 12I) is devoid of a protruding clamping lip having a surface facing the upper surface. opposing upper and lower surfaces (12D, 12E), opposing longitudinal side surfaces and opposing lateral side surfaces extending transversely to and connecting the opposing longitudinal side surfaces; a cutting insert through bore passing between the opposing upper and lower surfaces (12D, 12E); opposing first and second longitudinal walls (12F, 12G) extending between the upper and lower surfaces (12D, 12E) and between a portion of each of the longitudinal side surfaces and the through bore; and opposing first and second transverse walls (12H, 12I) extending between the opposing upper and lower surfaces (12D, 12E), and extending transverse, and connected, to the opposing first and second longitudinal walls (12F, 12G); wherein: the cutting insert through bore is bounded by inner surfaces (12F1, 12G1, 12H2, 1212) of the opposing first and second longitudinal walls (12F, 12G) and of the opposing first and second transverse walls (12H, 12I); and each of the inner surfaces (12F1, 12G1) of the first and second longitudinal walls (12F, 12G) is formed with a protruding clamping lip (12F2, 12G2) which projects into the through bore, wherein each protruding clamping lip (12F2, 12G2) is spaced from the upper surface; characterized in that the cutting insert is elongated with a longitudinal cutting insert axis ( A H) extending through the center thereof via first and second ends (12A, 12B); the cutting insert through bore has an elongated shape in a plan view of the upper surface; and each inner surface (12H2, 12I2) of the first and second transverse walls (12H, 12I) is devoid of a protruding clamping lip having a surface facing the upper surface. the cutting insert through bore is bounded by inner surfaces (12F1, 12G1, 12H2, 1212) of the opposing first and second longitudinal walls (12F, 12G) and of the opposing first and second transverse walls (12H, 12I); and each of the inner surfaces (12F1, 12G1) of the first and second longitudinal walls (12F, 12G) is formed with a protruding clamping lip (12F2, 12G2) which projects into the through bore, wherein each protruding clamping lip (12F2, 12G2) is spaced from the upper surface; characterized in that the cutting insert is elongated with a longitudinal cutting insert axis ( A H) extending through the center thereof via first and second ends (12A, 12B); the cutting insert through bore has an elongated shape in a plan view of the upper surface; and each inner surface (12H2, 12I2) of the first and second transverse walls (12H, 12I) is devoid of a protruding clamping lip having a surface facing the upper surface.