Abstract: The invention relates to a security barrier (10, 40, 60, 82), and a method (100) of installation thereof, and in particular, although not exclusively, to the installation thereof to a bridge structure (70). The security barrier (10, 40, 60, 82) comprises a support (12 62, 72) having at least one upright barrier member (14, 64, 85) thereon. The support (12, 62, 72) is for positioning substantially at ground level (41, 69, 72) and has a portion that is substantially planar with a leading edge (29). The at least one barrier member (14, 64, 85) is at the leading edge (29) or adjacent to the leading edge (29). The portion is for receiving a covering (75) thereon for adding mass to the security barrier (10, 40, 60, 82) and for biasing it towards the ground level (41, 69, 72). Two adjacent security barriers (10, 40, 60, 82) can be secured to each other with a joining member (200) to connect two adjacent barrier members (14) of the two adjacent security barriers (10, 40, 60, 82).