The Uniform Network Code is the hub around which the competitive gas industry revolves, comprising a legal and contractual framework to supply and transport gas. It has a common set of rules for all industry players which ensure that competition can be facilitated on level terms. Network Code came into effect in March 1996 after two years of negotiation between Transco and the shippers.
In 2005 as a result of the sale of four of the gas distribution networks, the Network Code was replaced by the Uniform Network Code (UNC). The UNC is managed by the Joint Office of Gas Transporters.