9 Fibre optic sensor system for use in monitoring and assessing the safety, stability and integrity of oil, gas and water pipelines, telecommunication networks, cables, rail tracks, rail networks; fibre optic sensor system for use in border and perimeter security; acoustic sensing apparatus; intruder detecting sensors; sensors incorporating optical fibres; signal transmitting apparatus utilising optical fibres; hydrophones; accelerometers; accelerometers integrating global positioning apparatus; computer software for use in pipeline, cable, rail track, border, perimeter and security monitoring systems; computer software for recording and identifying non-musical sounds for use in monitoring and assessing the safety, stability and integrity of oil, gas and water pipelines, telecommunication networks, cables, rail tracks and rail networks; downloadable non-musical sound recordings in the form of digital code; non-musical sound data recorded in electronic form; non-musical sounds, data and code downloadable or provided on recorded data carriers