Note: This advice is given by the CAP Executive about non-broadcast advertising. It does not constitute legal advice. It does not bind CAP, CAP advisory panels or the Advertising Standards Authority.


The requirement to display fuel consumption ('mpg') and CO2 emissions figures on advertisements is not a specific requirement of the CAP Code. However, if a business is involved in the supply of new cars in the UK, they must provide certain information as it is a statutory requirement.

The legislation that sets out the requirements for the display of that information is The Passenger Car (Fuel Consumption and CO2 Emissions Information) Regulations 2001 and amending 2004 and 2013 Regulations.

What are the figures based on?

Before September 2017, all cars advertised had CO2 and fuel consumption values based on the New European Driving Cycle test (NEDC). The new Worldwide Harmonised Light Vehicle Test Procedure (WLTP) is a new test cycle for cars, intended to produce more realistic CO2 and fuel consumption values. The new testing regime aims to provide a closer representation of ‘real-world’ fuel consumption and CO2 figures.

So will all adverts now use WLTP?

The transition to WLTP will happen in phases. First, the WLTP testing regime officially applies to new types of car from September 2017. New types of cars are vehicle models that are introduced on the market for the first time. WLTP will apply to all new car registrations from September 2018.

Who ensures adverts are compliant?

The Vehicle Certification Agency (VCA) is the nominated UK enforcement body in monitoring all car advertisements to ensure they display the relevant fuel consumption and CO2 data. The VCA requires that text is easy to read, easily understandable and ‘no less prominent than the main part of the information.’ To help marketers and their agencies, the VCA has published Guidance Notes, to further clarify the requirements for advertising (these were updated November 2014).

If you want to enquire about the requirement or the guidance, please contact the VCA direct on: adverts@vca.gov.uk or telephone: 0117 952 4169

Does the CAP Code apply?

These statutory figures, in and of themselves, are not regulated by the ASA, and the CAP Code does not apply in terms of the inclusion or accuracy of the figures.  However, marketers should bear in mind that the CAP Code does still apply to claims made in ads and whether they are likely to mislead consumers.  As with all claims capable of objective substantiation, figures that relate to a vehicle’s fuel efficiency or emissions should be accurate and, if not to do so would mislead materially, the basis for their calculation should be adequately explained. 

For example claiming that a vehicle is capable of “returning a quite remarkable 68.9mpg on a combined cycle” should be representative of a figure likely to be achieved by consumers, or the basis for the figure should be suitably explained (Volkswagen Group UK Ltd t/a Audi, 27 March 2013).  Under the previous testing regime, the ASA accepted qualifications that made clear that the figures were obtained from laboratory testing, intended for comparisons between vehicles and may not reflect real driving results but this may no longer be necessary, or indeed suitable, under the new regime. 

Until the ASA rules on a similar situation under the new regime marketers are advised to follow the principle that, if the figures are not representative of what could actually be reasonably achieved by consumers, they should qualify them with an explanation of the conditions under which the figures were achieved and that, if applicable, they may not reflect actual consumer experience.


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