SEC v51.0 released to implement MP128B

11 November 2021

An updated version of the SEC came into effect on 11 November 2021 to implement MP128B ‘Incorrect Gas Network Operator Certificates’.

MP128B has amended the Post Commissioning obligations so that Suppliers can leave the Access Control Broker (ACB) Certificate in the Gas Network Operator (GNO) slot of a Gas Proxy Function (GPF) if there is no unrevoked GNO Certificate available in the Smart Metering Key Infrastructure (SMKI) Repository. It is now also optional instead of mandatory for GNOs to become Subscribers for SMKI Organisation Certificates.


What parts of the SEC were affected?

The following parts of the SEC were affected:

  • SEC Section B ‘Accession’
  • SEC Appendix AC ‘Inventory, Enrolment and Decommissioning Procedures’


Where can I access the redlining?

The redlined changes can be found on CodeWorks via the links below:


Our Document Log lists the versions of each SEC document now in effect following this release.

You can download the individual SEC documents from the SEC and Supporting Documents section of our website or via CodeWorks.


Where can I find further information?

Further information can be found on the MP128B page of our website. If you have any questions, you can call the SECAS Helpdesk at 020 7090 7755 or email