Please be advised that following the publication of Ofgem's decision letter and the associated Notice of Implementation for UNC Modification Proposal, National Grid will implement the requirements of UNC Mod 0257: "Revision of the Gas Balancing Alert (GBA) Trigger/Safety Monitor" from 06:00 on 01/10/09.

The GBA Trigger Level will continue to be published on Prevailing View but will be subject to change on a daily basis following the publication of the 13:00 day ahead forecast.  

Supporting information will be uploaded daily to the Gas Balancing Alerts pages within the Operational Data section of Nationalgrid.com.

The GBA Trigger Level information page on Nationalgrid.com has been amended to reflect these changes.

Details of the modification and OFGEMs decision letter can be found on the Gas Governance Website.