A network and method of laying network cables in water supply pipes is disclosed. A building is situated near a roadway along which is laid a trunk cable. A water supply pipe branches off the water main to enter the building. A water supply pipe is provided at the time of construction of the building and is an underground pipe. It is conventional to provide a dedicated (and usually underground) conduit for a branch cable, which is expensive and disruptive. In the present invention the branch cable is laid along water supply pipe, enabling the cable to cross between the trunk cable and the building with minimal disturbance of the ground therebetween. This is achieved by introducing cable to pipe by use of a suitable Y-junction at location and removing the cable from the pipe by use of a second such Y-junction at location.