A pipe coupling (11) comprises a tubular casing (12) and a sealing gasket (13), which fit over the ends of the pipes to be coupled. The casing (12) is formed from a strip of rolled steel into a cylindrical shape, with a longitudinal gap (14). The free ends of the strip, which forms the casing, are bent outwardly to form radially projecting flange (15) along opposite edges of the longitudinal gap (14). The outer ends of the flanges (15) are bent back at right angles to form stiffening flanges (16) along the longitudinal outer edges of the flanges (15). A bridging member (18) fits inside the casing so as to span the longitudinal gap. Tensioning screw bolts (25) pass through reinforcing plate's (20) and the flange (15). A hexagonal nut (34) is threaded onto the end of each screw bolt. The nuts fit into the channel but are prevented from turning. The heads (35) of the bolts have a hexagonal recess to take an Allen key so that they can be tightened to clamp the coupling around the pipe ends.