A method of reinforcing a fibre reinforced resin matrix composite structure, the method comprising: providing a composite structure having one or more holes formed therein, feeding a reinforcement rod through a passageway having one or more walls defining an inlet to the passageway, wherein the inlet to the passageway is dimensioned to prevent a rod having a maximum cross sectional dimension greater than a predetermined dimension from passing through the passageway, and in the event of the rod contacting the wall defining the inlet to the passageway stopping feeding of the reinforcement rod through the passageway, or in the event of the rod passing through the passageway without contacting the wall defining the inlet to the passageway inserting a portion of the rod into a hole in a composite structure wherein a rig may be provided for feeding rod through the passageway and for inserting the rod into a hole in a composite structure, and wherein the wall defining the inlet to the passageway is configured such that said wall may be impacted by a rod and in the event of the rod impacting the wall defining the inlet to the passageway, the method comprises stopping operation of the rig, and wherein the passageway is defined by a tube, and wherein the inner diameter of the tube is equal to a predetermined maximum cross sectional dimension of the rod, characterized in that the tube is arranged to slide when impacted by the rod and the method comprises detecting said sliding motion and stopping operation of the rig when said sliding motion is detected, and wherein a switch or motion detector is provided to detect sliding of the tube, and wherein said switch or motion detector is configured to send a signal to a control system to stop operation of the rig. providing a composite structure having one or more holes formed therein, feeding a reinforcement rod through a passageway having one or more walls defining an inlet to the passageway, wherein the inlet to the passageway is dimensioned to prevent a rod having a maximum cross sectional dimension greater than a predetermined dimension from passing through the passageway, and in the event of the rod contacting the wall defining the inlet to the passageway stopping feeding of the reinforcement rod through the passageway, or in the event of the rod passing through the passageway without contacting the wall defining the inlet to the passageway inserting a portion of the rod into a hole in a composite structure wherein a rig may be provided for feeding rod through the passageway and for inserting the rod into a hole in a composite structure, and wherein the wall defining the inlet to the passageway is configured such that said wall may be impacted by a rod and in the event of the rod impacting the wall defining the inlet to the passageway, the method comprises stopping operation of the rig, and wherein the passageway is defined by a tube, and wherein the inner diameter of the tube is equal to a predetermined maximum cross sectional dimension of the rod, characterized in that the tube is arranged to slide when impacted by the rod and the method comprises detecting said sliding motion and stopping operation of the rig when said sliding motion is detected, and wherein a switch or motion detector is provided to detect sliding of the tube, and wherein said switch or motion detector is configured to send a signal to a control system to stop operation of the rig.