September's Final Figures: What the ZEV Mandate Gap Now Requires

The SMMT published its final September registration figures this morning, and they confirm what the early numbers signalled: a record month for electric cars, and a year-to-date share still short of what the law asks for. Total registrations reached 350,536, up 12.0% on September 2025, the tenth consecutive month of growth and the strongest September since 2017. Battery electric cars accounted for 99,201 of those, a record volume and 28.3% of the market.

These are the final figures, the settled version of the release the SMMT first put out on 2 October, and they are the numbers the mandate arithmetic has to run on. Our report on the first reading covered that initial release; this is the confirmed set, and it changes little of the picture except to make it firm.

The month in full

Battery electric volume rose 36.3% against September 2025, when the share was 23.3%, so the market moved five percentage points in a year. Plug-in hybrids had the stronger month in percentage terms, up 55.5% to a record 59,571 and a 17.0% share. Hybrids without a plug went the other way, down 4.3% to 45,839 and a 13.1% share. Petrol registrations fell 6.7% to 131,864, still the largest single power source at 37.6% of the month, and diesel rose 11.5% to 14,061, a 4.0% share. Electrified vehicles together took a record 58.4% of the market.

Private buyers were the engine. Their registrations reached 149,166, up 13.9% and 42.6% of the month, against fleet's 190,998 units and 54.5% share.

The gap in numbers

The year-to-date picture is where the mandate comes into focus. Battery electric registrations for the first nine months stand at 454,947, which is 26.2% of the 1,739,271 cars registered in 2026 so far. The ZEV mandate requires 33% of this year's sales to be zero emission, and the current share is behind even the 28% target that applied last year.

The SMMT's own market outlook, at 2.183 million units for the full year, turns that into a single figure: a 33% share would need about 720,000 electric cars across 2026, and the SMMT puts the shortfall at roughly 265,000 additional electric registrations in the final quarter alone. Run the arithmetic one step further and the shape of the challenge appears. If the year closes at 2.183 million, the market has about 444,000 registrations left between October and December. Placing 265,000 electric cars inside that 444,000 means roughly 60% of the final quarter would have to be battery electric. September, a record month that lifted the industry's mood, ran at 28.3%.

That comparison is ours, worked from the SMMT's published figures rather than stated by the society, and it is the honest measure of the distance. The required monthly electric volume, around 88,000 cars a month, is actually below September's 99,201. What makes the task hard is the smaller base it has to sit inside, because the final quarter is a lower-volume period than the plate-change month.

What the flexibilities change

The mandate is not a simple pass or fail. It carries compliance flexibilities that let manufacturers trade credits with one another, borrow against future years, and lean on over-performance elsewhere. We set those mechanics out in our explainer on the mandate's flexibilities, and they matter here because they soften the headline gap without closing it. The SMMT refers to them directly, describing targets that continue to outpace demand "despite the range of regulatory flexibilities available".

The wider policy question is the Mandate review, which our halfway look at the review covered in September. Mike Hawes, the SMMT's chief executive, framed the stakes in precisely those terms.

Hawes on the record

Hawes called September's performance "a major achievement" and said high fuel prices were giving more consumers a reason to consider going electric. He was equally direct about the distance remaining. Uptake "remains behind mandated targets and, whilst flexibilities help, the UK still has the world's toughest targets and highest energy costs", he said, before describing the Mandate review as an opportunity to "build on this momentum and support consumers" while strengthening business viability and UK competitiveness.

What would close the gap

The industry's own answer is more affordable models, and the numbers give it some support. The SMMT counts 178 electric models on sale in the UK now, more than double the count of 2023, and it credits September's surge to that choice, to manufacturer discounts and to the Electric Car Grant. The cheaper end of the market is where the volume argument now sits, and today brought a fresh example: Hyundai opened UK orders for the IONIQ 3 at £18,495 after the full grant, which we cover here. The grant itself is capped at cars listed at or under £37,000, so it pulls in the same direction. Our autumn grants update tracks the models joining the list, and the budget question that hangs over it is whether that pipeline arrives fast enough to matter for this year or only for the ones after.

The honest read

September was a genuine record and a genuine sign of a maturing market. It was also a month that, at full volume and with heavy discounting, delivered 28.3% electric when the year needs 33%. The gap is not a crisis, and the flexibilities exist for exactly this kind of shortfall. It is, though, now a concrete task with a number attached, and that number lives in the final quarter.