A modular barrier includes a plurality of identical barrier sections. Each section 10 includes a base portion 12 surmounted by an upright portion 14. The upright portion has projections 16, 18 with substantially semicylindrical outer surfaces at its ends. Correspondingly shaped recesses 20, 22 are also provided. At a female end, the base portion 12 includes a nose 28. The surface of the nose is a surface of rotation of the profile of the base portion 12. At the male end, the base portion 12 includes a correspondingly shaped cavity 30. The first and second projections 16, 18 and nose 28 are provided with bores 32, 34, 36. When the female end of the barrier section 10 is brought up to a male end of a similar section, the projections mate with one another and the nose 28 is received in the cavity 30 of the similar section. A hinge pin (not shown) may then be passed through the bores 32, 34, and 36. By means of this device, one barrier section can be articulated to the next and the joint between the two base portions of adjacent barrier sections presents an essentially smooth profile irrespective of the angle between the two.