Insights
On 28 October 2026 every supplier must be ready for market wide half hourly settlement. A supplier that is not cannot take new customers. This is what the deadline actually means, and what to do with the time that remains.
Until the M14 deadline. By Christopher Fagan, PEF Consulting Partners. 4 September 2026.
M14, 28 October 2026: every supplier must have systems in place to accept meter points under the new MHHS arrangements. After this date reverse migration ends, meter points cannot return to the old regime, and a supplier that is not compliant cannot take new customers. M15, 7 May 2027: every meter point must be migrated, closing the eighteen month migration window. M16, 2 July 2027: settlement moves from the fourteen month timetable to a four month timetable, which means settlement errors stop being a slow leak discovered next year and become a fast one discovered this quarter.
For a growing supplier the M14 restriction is not a compliance footnote, it is a switched off growth engine. Acquisition spend keeps running, brokers keep sending customers you must refuse, and competitors take the volume. Price that per month of restriction and the cost of getting ready properly stops looking expensive. That arithmetic, not the regulatory letter, is why the laggards who move now will spend far less than the ones who move in January.
Three groups, honestly. Suppliers, especially smaller, non domestic and I and C suppliers without the delivery capacity of the largest players, who are behind on systems readiness, qualification or migration planning. Agent businesses, the meter operators, data collectors and aggregators, whose qualification and data capacity the whole arrangement depends on, and whose suppliers will hold them to it. And, quietly, everyone who is technically ready but whose data quality means their settlement position after cutover will be wrong, expensively, on a four month clock.
Triage first: establish honestly, this week, whether your readiness evidence, systems capability and migration plan would survive scrutiny, because the difference between amber and red decides everything else. If systems readiness is the gap, that is now the only priority, because it gates the deadline itself. If readiness is real but migration is behind, build the cohort plan for the window to May and secure the people to run it now, because the skills market tightens every month. And whatever your position, get your data quality and settlement arithmetic examined, because ready is not the same as right, and from July 2027 wrong surfaces in months.
Our free readiness check gives you an honest position in ten minutes, in your browser, across migration, data, settlement and operations. It is the fastest way to find out which conversation you should be having.
M14 is the first deadline, not the last. Once it passes, the question changes from whether you are ready to whether your migration and your data will hold.
Between now and M15 on 7 May 2027, every remaining meter point moves onto the new arrangements. With reverse migration gone, a meter point that moves with poor data stays on the new arrangements with poor data, so reconciliation before and after each move matters more than speed.
From M16 on 2 July 2027, the settlement timetable is four months instead of fourteen. Errors in registration, meter data or estimation that once washed through a year of reconciliation runs will land in the same financial year. If you are ready for M14 and want to know whether you are ready for what follows, see our settlement performance support.
PEF supports suppliers and agents through MHHS from delivery experience, including settlement and imbalance resolution inside a major UK supplier. Confidential, senior, and honest about where you stand.
Milestone dates are from the MHHS Programme's published plan. This article is guidance, not regulatory advice.