ZEV mandate 2026: What it means for used car buyers and the petrol car market

The Zero Emission Vehicle mandate is the single most influential piece of regulation shaping what cars are available in the UK, what they cost, and what your next used car will be worth. It has been in force since January 2024, it is currently under government review, and the outcome of that review will shape the used car market for the rest of the decade.

For used car buyers, the practical questions are simple. Is petrol about to become harder to find or more expensive? Are used EV prices going to keep falling? Is there a right moment to buy? This guide explains what the mandate actually does, where things stand as of September 2026, and what it realistically means for the cars on a used forecourt.

What the ZEV mandate actually is

The ZEV mandate is a legally binding rule requiring every car and van manufacturer selling in the UK to ensure a minimum percentage of their annual sales are zero-emission vehicles — in practice, almost entirely battery electric cars. It sits within the Vehicle Emissions Trading Schemes Order and was passed into law in January 2024.

The targets rise every year. For cars, the required zero-emission share was 22% in 2024, 28% in 2025, and 33% in 2026. It continues climbing to 38% in 2027 and 80% by 2030, before reaching 100% in 2035. Van targets are lower, at 24% in 2026 rising to 70% by 2030.

Importantly, this is a rule about what manufacturers must sell, not about what you are allowed to buy. There is no restriction whatsoever on buying, owning, or selling a used petrol or diesel car. Even after 2035, when all new cars sold must be zero-emission, the existing petrol and diesel fleet stays on the road and continues to change hands normally.

Manufacturers who miss their target face a fine for each non-compliant vehicle, but the system includes substantial flexibilities. They can bank credits from years where they overperform, borrow against future years, and trade credits with manufacturers who have exceeded their own targets. There are also separate provisions allowing manufacturers to convert reductions in the emissions of their petrol and diesel range into compliance credit.

Where things actually stand in 2026

The gap between the target and reality is the central fact of the 2026 market.

The 2026 target is 33%. Battery electric cars accounted for around 25.6% of new registrations across the year to August 2026, according to SMMT data. The industry outlook published in July expected BEVs to finish 2026 at around 27.4% — meaningful growth on 2025, but well short of the mandate.

The same picture applies to 2027. The target rises to 38%, while the current industry forecast sits at around 32.1%.

That shortfall is not because nobody is buying electric cars. Registrations are at record levels, with July 2026 seeing battery electric volumes up 44.5% year on year. The issue is that the targets rise faster than consumer demand has grown. The SMMT has noted that more than £12 billion in manufacturer discounting has been deployed to push electric volume, and that in its most recent survey of automotive business leaders, every single respondent considered the UK to be behind the trajectory needed for the 2030 target.

The August 2026 consultation: what is being reviewed

On 14 August 2026, the government opened a formal consultation reviewing the ZEV mandate. It is the first government review of the annual percentage targets and flexibility mechanisms since the scheme began, and it runs until 23 October 2026.

The consultation explores four alternative pathways for car targets from 2027 onwards, including one that would lower the 2030 headline target from 80% to 70%, and others that would reshape the annual trajectory to make the climb less steep in the middle years.

The government has been clear that the end goals are unchanged: new petrol and diesel cars are still due to be phased out in 2030, and all new cars and vans must be zero-emission by 2035. What is on the table is the shape of the path between now and then.

The arguments on each side are worth understanding, because the outcome genuinely matters for the used market.

The case for relaxing the targets, made most forcefully by the SMMT and several manufacturers, is that compelling supply does not create demand. Manufacturers are discounting heavily to shift electric volume, which damages profitability, weakens residual values, and diverts investment. They argue the targets should track actual consumer uptake more closely, and that the current trajectory risks UK competitiveness and jobs.

The case for holding firm, made by EV advocacy groups and several environmental analysts, is that the mandate is the main reason UK EV supply and choice have expanded so quickly, and that the discounting manufacturers complain about is exactly what has made electric cars affordable to more buyers. Weakening the targets now, they argue, creates a cliff edge in 2030 when flexibilities expire and much tougher requirements arrive all at once.

Both positions rest on genuine evidence. The consultation outcome is not yet known and will not be settled until after 23 October at the earliest.

What this means for used petrol and hybrid cars

This is where it gets practical, and the picture is more nuanced than the headlines suggest.

Used petrol is not going anywhere. SMMT data for the second quarter of 2026 shows petrol accounted for 1,121,243 used transactions and diesel 620,045. Conventionally fuelled cars made up 86.7% of all used car sales in the quarter. Even on the fastest transition scenario, the used market will be overwhelmingly petrol and diesel for many years — the cars being sold used today were registered new years ago, and the used market always lags the new market by roughly three to five years.

Petrol volumes are gently declining, not collapsing. Used petrol transactions fell 1.2% year on year in Q2 2026. That is a soft drift, not a supply crunch. Superminis — overwhelmingly petrol — remain the single most popular used purchase at 31.7% of the market.

Diesel is the segment genuinely tightening. Used diesel transactions fell 7.2% in Q2 2026, and the SMMT attributes this directly to reduced supply coming through from the new car market, where diesel now accounts for under 5% of registrations. Fewer diesels sold new several years ago means fewer diesels reaching the used market now. For buyers who specifically want a diesel — for towing, high mileage, or long motorway commutes — choice will continue to narrow, and well-maintained examples are likely to hold value relatively firmly because supply is shrinking.

Hybrids are the clear growth story. Used hybrid transactions rose 27.6% in Q1 2026. Hybrids were also explicitly given a longer runway in the 2025 changes to the mandate, remaining available new until 2035 rather than 2030. That combination of strong demand and continued new supply makes used hybrids one of the more stable segments to buy into.

What this means for used EV prices

The mandate has had a very direct effect on used electric car values, and it has been good news for buyers.

Because manufacturers need electric volume to hit their targets, they have discounted new EVs heavily and pushed substantial finance incentives. Those discounts flow directly into used values — a heavily discounted new car becomes a cheaper used car two or three years later. Add a wave of ex-fleet and ex-lease returns from the earlier adoption years, and used EV prices have fallen a long way from their 2022 peak.

Demand has responded. Used battery electric transactions hit a record 110,761 in Q2 2026, up 67% year on year — the strongest quarterly growth since early 2024. Used EVs are no longer a niche purchase.

What happens next depends partly on the consultation. If targets are relaxed, the pressure on manufacturers to discount new EVs eases somewhat, which over time would support used values — slightly worse for buyers, slightly better for existing owners. If targets hold, the discounting continues and used EV values stay under pressure, which favours buyers.

Either way, the more important driver for most buyers is simply that the used EV market has matured. There is now genuine choice at every price point, battery health data is available, and the cars themselves are better understood.

So is now a good time to buy petrol, or should you switch?

The honest answer is that the mandate should not be the deciding factor for most used car buyers. It shapes the market, but it does not create urgency in either direction. A few practical points matter more.

If you are buying petrol: there is no supply cliff coming in the used market. Petrol cars will be bought and sold normally for well over a decade. The things that should influence your decision are the same as always — running costs, insurance, reliability, and whether the car suits your use. Current pump prices, which have risen sharply through 2026, are a more immediate consideration than any regulatory timetable.

If you are considering a used EV: the case rests almost entirely on whether you can charge at home. With off-peak home charging, running costs are dramatically lower than petrol. Without it, relying on public rapid charging, an EV can cost more per mile than a petrol car. That single question matters far more than the ZEV mandate.

If you want a diesel: this is the one area where timing genuinely applies. Supply is tightening measurably, choice is narrowing, and good examples are getting harder to find. If a diesel suits your mileage and towing needs, there is a reasonable argument for not waiting too long.

If you are unsure: a hybrid is currently the lowest-regret option. Strong used supply, growing demand, no charging infrastructure requirement, better fuel economy than petrol, and a regulatory runway extending to 2035.

What will not change

It is worth being clear about a few things the mandate does not do, because they are widely misunderstood.

It does not ban you from driving a petrol or diesel car, now or after 2030 or 2035. It does not force you to scrap an existing car. It does not restrict the sale of used petrol and diesel cars at any point — the 2030 and 2035 dates apply only to new car sales. And it does not set any target for what proportion of used cars must be electric.

If you own a petrol car today, you will be able to keep driving it, servicing it, and eventually selling it in the normal way for many years to come.

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