Car manufacturers will now have to display how much fuel their cars consume and how much they pollute on advertising billboards.
The companies are obliged to do so under an EU Directive (1999/94 EC), but the Government in this country had misinterpreted the rule, wrongly exempting car makers from putting the information on billboards in this country.
The error was pointed out to the Government in a letter from environmental pressure groups, including Friends of the Earth, which threatened a judicial review if the Government's guidelines were not changed.
The directive says that 'Member states shall ensure that all promotional literature contains the official fuel consumption and official specific CO2 emission data of passenger car models.'
It also defines 'promotional literature' as 'a minimum as technical manuals, brochures, advertisements in newspapers, magazines and trade press and posters', and that the information should 'be easy to read and no less prominent than the main part of the information provided in the promotional literature'.
However, the Government's guidelines differed, believing that the EU's definition referred to material with 'a significant textual content'. The guidelines said 'We do not consider the majority of street advertisements to be within the scope of the regulations.'
Now, though, the Department for Transport (DfT) has said that 'we have been reviewing this guidance and have concluded that our guidance is incorrect... and now consider that street advertisements are subject to the requirements of the regulations'.