👉 In short: from 2026, PHEVs cost more in company car tax

If you’re set on one, you may want to order before the change

From 1 January 2026, the government is changing how plug-in hybrids (PHEVs) are tested for their “official” CO₂ emissions

Right now, the tests assume you drive your PHEV mostly on electric. In reality, many drivers don’t plug in as often, so they use the petrol engine more — and produce more emissions

The new test will assume less electric driving and more petrol driving, which means the official CO₂ figures for most PHEVs will go up

Why does this matter to you?

Company car tax (Benefit-in-Kind, BIK) is based on CO₂ emissions.

If your PHEV’s official CO₂ figure goes up, your tax band will also go up.

This means you’ll likely pay more tax each month for the same car — unless you register it before the new rules kick in

Key points for you

If you already have a PHEV before 1 Jan 2026, nothing changes — your tax stays based on the old test.

If you get a new PHEV after Jan 2026, expect higher CO₂ numbers and higher tax bills than you see in today’s brochures

PHEVs with longer electric ranges will still do better, but many popular models will lose some of their tax advantages

Pure electric cars (BEVs) are not affected — they remain at 0g/km O₂