CMA Energy Licence Modification Appeals: Northern Gas Networks Appeal Upheld and Referred Back to GEMA as 31 October Statutory Deadline Expires
The Competition and Markets Authority (CMA) has been determining appeals by five gas distribution companies against GEMA's RIIO-GD3 licence modifications, which set out how much energy companies can charge customers following Ofgem's price control decisions of 4 December 2025. The five companies, Cadent Gas, Northern Gas Networks, and Southern Gas Networks and Scotland Gas Networks (filing jointly), and Wales & West Utilities, sought permission to appeal on 3 March 2026 against modifications to their gas distribution licences made on 3 February 2026. On 29 October 2026, Northern Gas Networks (NGN) published a statement confirming that the outcome of its appeal was published on 29 October 2026. NGN CEO Mark Horsley stated the CMA upheld NGN's appeal and referred the matter back to GEMA, recognising errors raised through the statutory process. The CMA's case page, last updated 9 September 2026, records a statutory deadline of 31 October 2026 for final determinations, extended by one month following a 4 September 2026 CMA decision after representations from the parties. Citizens Advice was granted permission to intervene on grounds relating to Ongoing Efficiency.
Why this matters
Energy licence modification appeals to the CMA are rare and high-stakes: the RIIO-GD3 price control framework governs billions in allowable revenue for gas distributors over the next regulatory period, directly affecting network investment and consumer bills. A successful appeal, with the matter referred back to GEMA, opens the possibility that Ofgem must recalibrate its original price control determinations, which could increase allowed revenues for the affected networks. The outcome for NGN signals that at least one appellant has secured a substantive concession, creating pressure on GEMA's methodology and potentially affecting the determinations for other appellants whose outcomes have not yet been publicly confirmed. The imminent 31 October statutory deadline means the legal landscape here is resolving in real time.
On the Ground
This activates regulatory disputes, energy regulatory, and administrative law practices. Firms advising gas distribution networks will be reviewing the CMA's reasoning once full determinations are published, assessing grounds for further challenge or compliance steps. GEMA will need specialist regulatory counsel to manage the remittal process. A trainee on this matter would be tasked with reviewing the CMA's published determination documents, preparing a comparative analysis of each appellant's grounds, and summarising the remittal scope for supervising partners.
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