A closure assembly for terminating an end of a pipe (4) has an end-cap (4) holding and having fluid-tight connection to a mutually coaxial cylindrical plug (2) and circular collar (3). The plug (2) and the collar (3) are configurable between respective engaged and disengaged configurations and mutually spaced to provide an annular space therebetween when the plug (2) and collar (3) are in their disengaged configurations. The annular space is arranged to receive an end of a pipe (1) arranged coaxially with the plug (2) and collar (3), the plug (2) and collar (3) being respectively slidable into and over the end of the pipe (1). The plug (2), when in its engaged configuration, grips the inner face of said pipe (41) and to provide a fluid tight seal and the collar (3), when in its engaged configuration, grips the outer face of the pipe (1) and to provide a fluid tight seal.