The Gas Transmission Charging Methodology Forum (TCMF) is an industry forum set up by National Grid Gas (NGG) that provides the means for transmission users to raise issues and provide comments on NGG modification proposals to its charging methodologies.
Once the proposals have been formulated and consulted upon, Ofgem assesses the modifications against charging methodology objectives. Ofgem normally makes a decision as to whether or not to veto the proposed modification within 28 days of receipt of the final modification report (or within three months if an Impact Assessment is conducted).