Following extensive analysis of GEMA’s Final Determination on the RIIO-GD3 Licence Modifications, published 3 February 2026, the Board of Gas distributor Northern Gas Networks (NGN) has unanimously decided to appeal the outcome to the Competition and Markets Authority (CMA).
The appeal will be submitted on 3 March 2026, with an outcome expected in Autumn 2026.
NGN CEO, Mark Horsley said: “NGN is a consistently high performing company in the gas distribution network industry.
“NGN’s RIIO-GD3 investment plan is designed to deliver a fairer, greener future for the North of England, and at the heart of NGN’s strategy is our desire to deliver efficiency gains for the benefit of our customers in a sustainable way.
“The Final Determination gives us clarity on what we need to deliver for our customers, and we’re in great shape as a business to continue doing this from April.
“We do, however, consider that there is a fundamental error on a specific aspect of the Determination that we are asking the CMA to adjudicate and conclude on.
“We will be following the formal regulatory process in order to seek a resolution and correct this error.”
NGN’s grounds of appeal will centre on a key issue relating to GEMA’s approach to calculating Ongoing Efficiency, which risks negatively impacting customers.
NGN is the gas distribution network for the North East, northern Cumbria and much of Yorkshire, transporting gas to 2.9 million homes and businesses across the region.