Legality of Decat Pipes – All you need to know

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Decat Pipes are designed to replace your vehicle’s catalytic converter, removing back-pressure from the engine and offering a smoother engine performance. The process is highly popular among motor enthusiasts and tuners, owing to the range of benefits that decatting offers.

However, as decatting involves removing your car’s catalytic converter, it may raise the question; are decat pipes legal? This article discusses this question in detail.

Are Decat Pipes Legal?

Image for a decat downpipe page call to action

Whether a decat pipe is legal on UK road depends on the emssions the vehicle creates after a decat has been fitted. The rules for emission control and catalytic converters are set by the Driver and Vehicle Licensing Agency or DVLA, and not the police. Emissions levels must be meet and if by fitting a decat pipe the vehicle no longer complies with the emissions standard set then it makes it illegal. The law states:

Under the Road Vehicles (Construction and Use) Regulations (Regulations 61(7) and 61A(3)) and the Road Traffic Act 1988 (Section 42) it is an offence to use on a road a vehicle which has been modified in such a way that it no longer complies with the air pollutant emissions standards it was designed to meet.


Under the Road Traffic Act 1988 (Section 75) it is an offence to alter a vehicle in such a way that the use of the vehicle on a road would be unlawful. A person altering the vehicle (if they knew or believed that the vehicle would be used on the road) could be found guilty of an offence under the Act.

The government recommends the use of catalytic converters in all vehicle models that came out after 2001. However, these are simply guidelines regarding the use of catalytic converters, and they certainly are not grounds for outlawing this practice.

Will Decat Pipes pass the MOT Test?

Picture of a MOT certificate form

One question that arises when decatting is whether or not your vehicle will pass the annual road-worthiness test, which is mandatory by the Ministry of Transport for all vehicles. No, your vehicle will not pass the MOT test, resulting in the cat being deemed unfit for the UK roads.


Decatting your vehicle may mean its no longer road legal in the uk. However, certain considerations need to be kept in mind, such as the annual MOT test.

Get your decat exhaust pipes from Turborevs today and take your car’s performance to new heights.

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