Diesel particulate filters on vehicles in the UK: what GOV.UK says
What the government guidance note and the road vehicle regulations say about diesel particulate filters on diesel vehicles in Great Britain, how the MOT test treats a missing filter, and where filter status meets clean air zone rules.
Checked against the sources at the bottom of this page on October 9, 2026. Rules, fees and pay change: the source has the last word.
This page reports what the official source says. It is not legal advice: ask the office named here. It restates a GOV.UK guidance note, a regulation and two GOV.UK service pages, and it does not describe how a filter works in the workshop or how to clean or service one. The guidance note is licensed under the Open Government Licence v3.0.
The guidance note
The Driver and Vehicle Standards Agency and the Department for Transport publish a guidance note called Diesel particulate filters on vehicles. GOV.UK shows it as first published on September 24, 2013 and last updated on December 4, 2013, so its wording and penalty figures date from then. The note describes a diesel particulate filter (DPF) as a device fitted to a diesel vehicle that filters particulate matter from exhaust gases, and says removal of one "will almost invariably contravene" the emissions requirements and makes the vehicle illegal for road use. It explains that a filter must be emptied of trapped soot by a process called regeneration, that regeneration done badly can lead to soot build-up and expensive repairs, and that this has led some owners to remove their filters. It then says removal has both legal and social implications. See the GOV.UK diesel particulate filters guidance note.
What the MOT test checks
The note says that since February 2014 the exhaust inspection in the MOT test includes a check that a DPF is present. A missing DPF, where one was fitted when the vehicle was built, results in an MOT failure. It adds that a vehicle can pass the visible smoke test anyway, a test it says is mainly meant to find vehicles in a very poor state of repair.
The regulation
The note says it is an offence under regulation 61A(3) of the Road Vehicles (Construction and Use) Regulations 1986 to use a vehicle that has been modified so that it no longer meets the air pollutant emission standards it was designed to meet. It states the possible fines as up to GBP 1,000 for a car and GBP 2,500 for a light goods vehicle. The text of regulation 61A on legislation.gov.uk applies to motor vehicles first used on or after January 1, 2001. Paragraph (3) bars using, or causing or permitting use of, a vehicle on a road if it does not meet the limit values that apply to it, unless three conditions are all met. Those conditions are that the failure is not caused by a change made to the propulsion unit or the exhaust system, that normal periodic servicing would not bring the limits within reach, and that the failure does not result from an emission control device being other than in good and efficient working order. See regulation 61A on legislation.gov.uk.
Where filter status meets the zones
The GOV.UK clean air zone guidance, which applies to England, sets Euro VI as the minimum standard for heavy goods vehicles and buses to avoid a charge, and Euro 6 for diesel vans and cars. It lists national exemptions that include a vehicle fitted with retrofit technology approved under the Clean Vehicle Retrofit Accreditation Scheme. It does not mention the DPF by name. See GOV.UK on driving in a clean air zone. The zone rules for London and Scotland are on the guide to low and ultra-low emission zones for work trucks.
Looking up a vehicle's MOT record
GOV.UK has a service to check the past results of a vehicle's MOT tests from its number plate. For cars, motorcycles and vans it holds results for tests done since 2005, and for heavy goods vehicles, trailers, buses and coaches for tests done since 2018. It shows where each test was done and which parts failed or had minor problems. See GOV.UK on checking a vehicle's MOT history.
At a glance
| Item | What the sources say |
|---|---|
| MOT | A missing filter that was fitted when built is an MOT failure, from February 2014 |
| Regulation | Road Vehicles (Construction and Use) Regulations 1986, regulation 61A(3) |
| Fines as the 2013 note states | Up to GBP 1,000 for a car, up to GBP 2,500 for a light goods vehicle; heavier vehicles not stated |
| Clean air zone minimum | Euro VI for heavy goods vehicles; Euro 6 for diesel vans |
| MOT history online | Heavy goods vehicles and trailers from 2018; cars and vans from 2005 |
Sources
- Driver and Vehicle Standards Agency and Department for Transport, diesel particulate filters guidance note, 2013, read October 9, 2026
- legislation.gov.uk, Road Vehicles (Construction and Use) Regulations 1986, regulation 61A, read October 9, 2026
- GOV.UK, Clean Air Zones guidance, read October 9, 2026
- GOV.UK, check the MOT history of a vehicle, read October 9, 2026
- GOV.UK, diesel particulate filters guidance note, publication page with first-published date, read October 9, 2026