A pipe coupling comprising: a tubular casing, having a longitudinal gap between a first free end and a second free end, for fitting around a pipe; a tensioning system for tightening the casing around the outer surface of the pipe, the system comprising: a first pivoting member, extending radially from the first free end of the tubular casing; a second pivoting member, extending radially from the second free end of the tubular casing, having a projection located at a distal end of the second pivoting member and extending towards the first pivoting member; a bridge plate located inside the casing for spanning the longitudinal gap between the first free end and the second free end of the tubular casing; at least one fastener; and means for restraining radially the projection of the second pivoting member relative to the first pivoting member, comprising: a slot and key arrangement, wherein the first pivoting member is provided with a slot having a main axis along the longitudinal direction and the projection of the second pivoting member having a key adapted to engage with the slot of the first pivoting member to substantially prevent relative radial movement between the first pivoting member and the second pivoting member, wherein, upon tightening the or each fastener, the first pivoting member and the second pivoting member pivot about the projection, and the first pivoting member and the second pivoting member resiliently bend about the first free end of the tubular casing and the second free end of the tubular casing respectively, such that each proximal end of the first pivoting member and the second pivoting member are drawn together to both tighten the casing around the outer surface of the pipe and to apply a radial force to the bridge plate. a tubular casing, having a longitudinal gap between a first free end and a second free end, for fitting around a pipe; a tensioning system for tightening the casing around the outer surface of the pipe, the system comprising: a first pivoting member, extending radially from the first free end of the tubular casing; a second pivoting member, extending radially from the second free end of the tubular casing, having a projection located at a distal end of the second pivoting member and extending towards the first pivoting member; a bridge plate located inside the casing for spanning the longitudinal gap between the first free end and the second free end of the tubular casing; at least one fastener; and means for restraining radially the projection of the second pivoting member relative to the first pivoting member, comprising: a slot and key arrangement, wherein the first pivoting member is provided with a slot having a main axis along the longitudinal direction and the projection of the second pivoting member having a key adapted to engage with the slot of the first pivoting member to substantially prevent relative radial movement between the first pivoting member and the second pivoting member, wherein, upon tightening the or each fastener, the first pivoting member and the second pivoting member pivot about the projection, and the first pivoting member and the second pivoting member resiliently bend about the first free end of the tubular casing and the second free end of the tubular casing respectively, such that each proximal end of the first pivoting member and the second pivoting member are drawn together to both tighten the casing around the outer surface of the pipe and to apply a radial force to the bridge plate. a first pivoting member, extending radially from the first free end of the tubular casing; a second pivoting member, extending radially from the second free end of the tubular casing, having a projection located at a distal end of the second pivoting member and extending towards the first pivoting member; a bridge plate located inside the casing for spanning the longitudinal gap between the first free end and the second free end of the tubular casing; at least one fastener; and means for restraining radially the projection of the second pivoting member relative to the first pivoting member, comprising: a slot and key arrangement, wherein the first pivoting member is provided with a slot having a main axis along the longitudinal direction and the projection of the second pivoting member having a key adapted to engage with the slot of the first pivoting member to substantially prevent relative radial movement between the first pivoting member and the second pivoting member, a slot and key arrangement, wherein the first pivoting member is provided with a slot having a main axis along the longitudinal direction and the projection of the second pivoting member having a key adapted to engage with the slot of the first pivoting member to substantially prevent relative radial movement between the first pivoting member and the second pivoting member, wherein, upon tightening the or each fastener, the first pivoting member and the second pivoting member pivot about the projection, and the first pivoting member and the second pivoting member resiliently bend about the first free end of the tubular casing and the second free end of the tubular casing respectively, such that each proximal end of the first pivoting member and the second pivoting member are drawn together to both tighten the casing around the outer surface of the pipe and to apply a radial force to the bridge plate.