Car billboard adverts will have to show climate impact following the Government’s decision to change its advertising guidelines.

Fuel consumption and CO2 emissions will now have to be prominently displayed.

Previously, the Government exempted ‘primarily graphical’ adverts from an EU directive on car advertising which says that fuel economy and CO2 emissions information must be prominently provided in all promotional literature.

The Society of Motor Manufacturers and Traders would not comment on whether it was a good idea but acknowledged that the motor industry is one of the most highly regulated and said it has always complied with advertising standards.

No compliance date has been set but the Department for Transport has said future advertising must meet the terms and existing advertising should be amended as soon as reasonably possible.

Daniel Burgess, HPI automotive director, supported the step but said the guidelines should go even further to include the used car market. Burgess has also previously called for the new car CO2 energy certificates to be extended into the used market.

The Government decision follows the threat of legal proceedings by the Alliance Against Urban 4x4s and Friends of the Earth.

Phil Michaels, head of legal at Friends of the Earth, said: “Until now the UK was getting away with flouting EU legislation on car advertising – but our legal action has closed the loophole.”