A remap and a delete are not the same job. The Department for Transport’s 2026 consultation is about holding a vehicle to the emissions standard it was built to. It is not a ban on tuning, and it is not yet a new MOT test.

The consultation, Regulating environmental impact of in-use emissions of road vehicles, was published on 6 July 2026 and closed on 6 September 2026. The department says it envisages legislation in the summer of 2027, followed by a lead-in of about six months before the law would be active. That timetable can still move when the government publishes its response. Until then, nothing in that document has changed the MOT manual.

What the proposal actually names

The Department for Transport says ordinary modification is a legitimate part of tuning and repair. The changes it says it would always treat as unlawful, because of their effect on the emissions limits a vehicle was built to meet, are specific:

  • removal or deletion of a diesel particulate filter, or a petrol particulate filter
  • removal of a catalytic converter
  • an AdBlue or SCR delete
  • EGR manipulation, whether the valve is blanked or the change is made in the ECU software

Enforcement, if this goes ahead, is expected to sit with the DVSA. The consultation says the annual MOT cannot currently see every emissions fault, so the intended pressure is on the modification itself, not only on whether a smoke test happens to pass.

What the MOT does today

Since February 2014 the MOT has included a visual check for a diesel particulate filter. If a factory-fitted filter is missing, or it is obviously tampered with, that is a fail. The smoke test is a weak way to find a filter that has been emptied and refitted so that it still looks original. That is why particulate-number testing, already used in the Netherlands and Belgium, has been on trial with DVSA garages. Great Britain has not set a date to add that test to the MOT. A later NOx check, which would be more likely to see an AdBlue delete, is being argued for by parts of the trade. It is not a confirmed test.

There is a separate legal point. Regulation 61A of the Construction and Use Regulations was not kept up to date when Euro 5 and Euro 6 arrived, and the consultation exists to close that gap. A missing DPF can already fail an MOT, and the government’s own DPF guidance already describes removal as illegal for road use. The 2027 proposal is about making the in-use rule follow the standard the vehicle was actually built to, including newer cars and vans.

What this means for a remap

A Stage 1 or Stage 1+ calibration at Llandow is for a healthy standard car. It does not require the exhaust, the DPF, the EGR or the catalytic converter to be removed. We check the car, the fuel and the logged data before offering Stage 1+. That is a different piece of work from a delete. Euro 7, which the Department for Transport has proposed for new car and van registrations, is a standard for new vehicles. It is not an MOT change for the car you already own.

If you are booking a road car, ask whether the calibration leaves the particulate filter, the catalyst, the EGR and the AdBlue system in place. If the car already has a warning, a restart countdown or a blocked-filter fault, start with a diagnosis. We can look at DPF faults and AdBlue faults, and the wider notes are in our FAQ. To price a calibration, check the car.