There is provided a deterrent device 10 having an elongate body 11 formed from an extrudable insulating material. The device has at least one elongate knitted/braided metallic conductor 19 on an upward facing surface of the body 11, the material of the body penetrating into the lower margins of the or each conductor thereby securing the or each conductor to the body with the upward facing surface of the or each conductor being exposed. This construction enables the conductors to be co-extruded with the body thereby avoiding the need for further fastening devices and enables manufacture in a single operation.