The research found that in the large majority of situations where temporary and demountable systems have been used, they have provided adequate protection. There have been some occasions however where operational processes or inaccurate hydraulic assessments has led to a failure of the systems. These failings highlighted the importance of reinforcing the performance and failure characteristics of temporary and demountable systems, and the role of the understanding of the hydraulic loading and operational management within this. They also highlighted that these systems only perform their flood protection role when fully in place before inundation occurs and the importance of the success of the associated operational processes within this. The guide therefore focuses on the whole life cycle of the design and management of the systems and associated products to ensure the development of an appropriate product and the achievement and continued maintenance of an optimum level of reliability. These are underpinned as necessary by an understanding of the risk and performance issues, including how the risk can be minimised and performance enhanced. The guide takes a user through a systematic process from deciding whether the use of temporary and demountable systems are appropriate for particular scenarios, through the design of systems that offer appropriate solutions to the required functional, structural and operational requirements. It then provides guidance on optimising the operational reliability and taking other local, economic, environmental and whole life management issues into consideration to enable the design to be finalised. This is supported by Appendices containing information on available products and their characteristics to aid design choices. The user is then guided through the development of operational support plans and protocols to ensure the system and associated products can be managed effectively over its life.