A support clamp (10) securable to a motor vehicle crash barrier (1), a barrier assembly and a method of securing a support clamp to a motor vehicle crash barrier. The support clamp of the present invention is securable to a motor vehicle crash barrier, the barrier having an elongate edge running the length of the barrier and at least one corrugation extending transverse to the edge. The clamp comprises a first jaw member (12) having opposing first and second ends, a second jaw member (14) having opposing first and second ends, and a hinge (46), connecting the first ends of the first and second jaw members, such that the first and second jaw members are rotatable about the hinge to open and close said clamp. In use, when the edge of the barrier is placed between the first and second jaw members and the second ends of the jaw members are pressed towards each other, the clamp grips the corrugation of the barrier such that the clamp is rigidly secured to the edge of the barrier without the need for additional fixing means.