The Interface Agreement, though not used always, regulates the relationship between the construction contractor and the O&M contractor (with the private partner joining in some cases). The agreement allocates responsibility for services and risk that may affect the provision of those services as a result of issues related to the construction of the infrastructure. The Interface Agreement, thus, covers the relationship between the private partner's overall activities, construction, and O&M. Specifically this covers the situation where the private partner has a separate agreement for construction and a separate agreement for O&M.
Under these circumstances, there needs to be clarity of roles and responsibilities for the construction contractor and the O&M contractor for smooth project implementation and operations. This is the purpose of the Interface Agreement. It has been used in the UK and some other countries. The concept is a constituent of the formal structure of agreements supporting PPP arrangements in the Indian context.