A tool assembly configured for location on a section of a pipe is operable to both isolate a section of the pipe and perform an intervention into the pipe while maintaining pressure integrity. The tool assembly includes a clamp, a cutting tool and an isolation tool. In use, the clamp sealingly secures the tool assembly to the pipe, the cutting tool performs an intervention operation on the pipe, and the isolation tool isolates the section of pipe in order that repair or replacement of equipment can be effected.