The Government is expected to try to win concessions for Jaguar and Land Rover over new European vehicle emissions levels.
Industry sources said Britain may also seek to exclude niche manufacturers such as Malvernbased Morgan, from any legally-binding targets.
A Europe-wide crackdown on car pollution was attacked yesterday as a compromise that contradicted the EU's claim to be leading the way on climate change.
New proposals on cutting Co2 emissions have been drastically weakened after months of intense lobbying by European carmakers - particularly producers of luxury high powered vehicles.
The European Commission proposals fulfil a threat to the industry to legislate if voluntary Co2 curbs were not agreed.
Average car emissions currently run at 160 grams of Co2 per kilometre.
Under the proposed new legally-binding maximum, car makers will have to produce new cars not emitting more than 130 grams of Co2 by 2012.
But they were already supposed to have reached 120 grams two years ago.
Now the Commission says the 120 gram figure can still be reached by 2012, but manufacturers will only be accountable for achieving 130 grams, through improved car-making technology to improve fuel consumption: the other 10 grams saving will come from "other technological improvements" such as better tyres with less rolling resistance and by increased use of bio-fuels.
"This initiative should be seen in the broader context of the fight against climate change," said a Commission statement.
"Cars are an important part of the everyday lives of a large number of Europeans. However, car use has significant impacts on climate change insofar as it accounts for 12 per cent of the overall EU emissions of carbon dioxide.
"Consequently, the EU has committed itself to ambitious greenhouse gas reduction and energy efficiency improvement targets to which all relevant sectors of the economy should contribute."
But Green MEP Caroline Lucas said the compromise - and another announcement due today on aircraft emissions - exposed the Commission as "hypocritical".
She said: "Both run the risk of severely compromising the EU's strong rhetoric on climate change after concessions were made to the car and aviation industries.
"Just days after taking credit for leadership on climate issues at the Bali talks the EU is due to fail at the first real test of its own commitment."