One of the greatest challenges facing civil engineers in the 21st century is the stewardship of ageing infrastructure. Nowhere is this more apparent than in the networks of tunnels, pipelines and bridges that lie beneath and above the major cities around the world. Much of this infrastructure was constructed more than half a century ago and there is widespread evidence of its deterioration. Tunnels, particularly old ones, are prone to being influenced by activities such as adjacent construction, for instance piling, deep excavations and other tunnel construction. Excessive leakage and pipe bursts are frequent and usually unanticipated. Importantly, underground structures often cannot be inspected when they are being used by trains or due to other physical constraints. The fragility of old infrastructure also presents a challenge for new construction in congested urban environments. Little is known of the long-term performance of such infrastructure. These uncertainties and the importance of safety to users and consumers prompted the initiation of recent research projects investigating the prospect of damage detection and decision making and the use of novel materials to mitigate damage. Advances in the development of innovative sensors such as fibre optic sensors and micro electrical mechanical sensors (MEMS) offer intriguing possibilities that can radically alter the paradigms underlying existing methods of condition assessment and monitoring. Future monitoring systems will undoubtedly comprise Wireless Sensor Networks (WSN) and will be designed around the capabilities of autonomous nodes. Each node in the network will integrate specific sensing capabilities with communication, data processing and power supply. It is therefore the objective of this proposal to demonstrate how large numbers of sensors can be integrated into large-scale engineering systems to improve performance and extend the lifetime of infrastructure, while continuously evaluating and managing uncertainties and risks. This proposal is a joint project between the University of Cambridge and Imperial College London and comprises an integrated research program to evaluate and develop prototype WSN systems. The main objectives of this proposal are to bridge advances in modelling large-scale engineering infrastructure with advances in wireless sensor networks and to develop a low-cost smart sensing environment for monitoring ageing public infrastructure. Three application domains will be studied in detail: (i) monitoring water supply and sewer systems and (ii) monitoring tunnels and (iii) monitoring bridges. The complexity of the monitoring system requires the following research areas to be explored : sensor systems, wireless communications, autonomous systems, information management, programming and design tools, trust security and privacy, systems theory, human factors and social issues. Field trials will be carried out with London Underground Ltd., Thames Water, Highways Agency and Humber Bridge. Intel Corporation will support the project with hardware for the trials.