National Grid Electricity Transmission (NGET) intends to establish a framework for the provision of Sulphur Hexafluoride (SF6) leak repair, leak reduction and preventative treatment services across its portfolio of Gas Insulated Switchgear (GIS) and Gas Insulated Busbar (GIB) assets located at transmission substations throughout Great Britain. The framework is intended to increase the delivery of SF6 emissions reduction activities through the use of standardised contracting arrangements and approved repair methodologies. Appointed contractors will be responsible for the design, installation, testing, inspection and quality assurance of external, non-intrusive repair solutions that maintain asset integrity and operational performance while reducing or preventing SF6 leakage. Solutions may include permanent repairs, leak-rate reduction treatments, and preventative interventions, and will typically be required to be installed without taking equipment out of service where reasonably practicable. Contractors will be expected to provide technically robust, evidence-based solutions, operate under ISO 9001-compliant quality management systems, and fulfil the roles of Principal Contractor and Principal Designer under the Construction (Design and Management) Regulations 2015. The framework will enable NGET to respond efficiently to emerging SF6 emission reduction requirements across its transmission network. The anticipated term of the framework will be a 3-year initial term with 2 year extension options upon mutual agreement.