The present position of existing types of high-voltage cables is briefly reviewed and the reasons underlying the development of the gas-filled cable are given. After a brief description of the cable, the design is dealt with in detail.The cable construction and manufacture are described and then the physical behaviour of the cable in service is considered. Details of the accessories associated with the cable system are given and the routine type and research testing of both cable and accessories are discussed.After dealing with gas-pressure considerations of the cable system in service and installations carried out, a brief survey of the economic aspect of the cable is given.It is concluded that the cable system has certain special advantages and that since its technical and economic positions are sound it should, in the future, be a factor to be taken into consideration when schemes involving power transmission at voltages of 33 kV and upwards are envisaged.