Does my modified classic need an MoT?

If your modified classic is over 40 years old, it might not need an MoT test – but the onus is on you be truthful. Here’s what you need to know

New rules mean that classic vehicles over 40 years old in the UK will no longer need an MoT from 20 May, 2018. However, there is a clause that excludes some modified classics.

First of all, don’t panic – even if your classic is heavily modified, it won’t be outlawed by the new MoT rules. The worst-case scenario is that it will have to continue to have annual MoT tests. Also, these vehicles will not be checked or audited, so it’s entirely down to the owner’s judgement as to what works within the rules below. It’s imperative that you are truthful; if you’re not and something bad subsequently happens on the road, the consequences don’t bear thinking about – and you’ll be held responsible.

To be MoT exempt, the vehicle has to be registered as a ‘Vehicle of Historic Interest’ or VHI. Heavily modified vehicles shouldn’t be registered as a VHI. Again, this is down to the owner declaring whether or not the vehicle has been ‘substantially modified’.

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These regulations were drawn up by the Department for Transport with a lot of help and advice from the Federation of British Historic Vehicle Clubs. The aim was only to protect all vehicles that can reasonably be thought of as being of historic interest – and it’s about roadworthiness, not authenticity. It’s also about protecting classics from more stringent MoT testing in the future.

Vehicles that were modified in period – including specials – will be allowed to be registered as VHIs, and will therefore be exempt from the need for an MoT.

Vehicles that have been ‘substantially changed’ in the past 30 years will not be eligible to be registered as a VHI, but will simply need to be MoT’d each year, as they are currently. This is a rolling 30-year date.

What determines ‘substantial change’?

The phrase is defined within this document and outlined below in italics, along with what we understand this to mean.

Modifications in respect of axles and running gear changes made to improve efficiency,
safety or environmental performance
will not prevent the vehicle from being granted VHI status. So that means uprated brakes, seatbelts or electronic ignition. In addition, fuel injection or even a modern engine transplant also improve environmental performance...

Changes that are made to preserve a vehicle, when original-type parts are no longer reasonably available, will not prevent the vehicle from being granted VHI status.

Changes of a type that can be demonstrated to have been installed on your vehicle when it was still in production or in general use (within ten years of the end of production) will not prevent the vehicle from being granted VHI status.


Chassis (replacements of the same pattern as the original are not considered a
substantial change) or monocoque bodyshell including any sub-frames
(replacements of the same pattern as the original are not considered a substantial
This means you can reshell a classic and still keep VHI status.


Engine – alternative cubic capacities of the same basic engine and alternative
original-equipment engines are not considered a substantial change. If the number of cylinders in an engine is different from the original, it is likely to be – but not necessarily – the case that the current engine is not alternative original equipment.

So, upping your classic Mini’s 998cc A-series engine to a 1275cc A-series engine? You’ll be covered. Surprisingly, we think you could even get away with implanting a modern Ford Zetec engine into your Ford Anglia or a 1970s Porsche flat-six into a VW camper.

If an engine was fitted by the factory to the same model of car, then you can certainly do the same without it counting as a substantial change. A Rover V8 into an MGB is fine because there was an MGB GT V8 model from the factory.

Transmission, suspension and brakes

Axles and running gear – alteration of the type and or method of suspension or
steering constitutes a substantial change.

Alteration of the type and/or method of suspension or steering does count as a substantial change. Changing MacPherson struts to coilovers should be fine, but going from, say, leaf springs to coils, or a steering box to a rack, will mean you need an MoT.

Converting to power steering, either from the same model or with a modern electric power steering kit, should not count as a substantial change. However, as the steering system is so important, the set-up should certainly be professionally checked immediately after conversion.

The same goes for brakes. It’s fine to uprate them, either from a better-equipped model in the range or with aftermarket parts – but have them checked to MoT standard first time round.

There’s no problem changing the gearbox or the rear axle ratio.

Apply common sense, and if there’s any doubt, just default to keeping your vehicle MoT’d.

Q-plates and kit cars

A vehicle will be considered to have been substantially changed and will not be exempt from MoT testing if...

It has been issued with a registration number on a ‘Q’ prefix.

It is a kit car assembled from components from different makes and model of vehicle.

It is a reconstructed classic vehicle as defined by DVLA guidance.

It is a kit conversion, where a kit of new parts is added to an existing vehicle, or old parts are added to a kit of a manufactured body, chassis or monocoque bodyshell changing the general appearance of the vehicle.

However, if any of the four types of vehicle listed above is already taxed as a ‘historic vehicle’ and has not been modified during the previous 30 years, it can be considered a Vehicle of Historic Interest (VHI) – and hence MoT-exempt.

Classic commercial vehicles

For models that have been commercial vehicles, changes that can be demonstrated were being made when they were used commercially.

Still not sure? Here’s our full guide to the new MoT rules.

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