Parliament sources at "trialogue" talks on Tuesday to finalise the revision said MEPs flatly rejected a proposal that could have seen the creation of "A+++" and "A++++" efficiency classes for some products such as fridges for which "A+" and "A++" already exist.

The Swedish presidency compromise only had the support of eight other EU governments, one source claimed. Countries such as Germany and the UK want to limit the number of classes that can be added to the A-G scale, ENDS understands.

The parliament could accept a compromise that would create "A+" and "A++" classes for a limited period before a formal re-scaling of the closed A-G scale, the source said. The parliament wants adverts for products carrying the label to include data on energy use and oblige public authorities to procure only labelled products where possible.

"The parliament will have to compromise on one of these issues, but it isn't clear yet which one it will be," the source told ENDS. A further round of trialogue talks is expected to be scheduled for next week.

*Meanwhile MEPs and EU governments made little progress in separate trialogue talks on Tuesday to finalise a revision of EU rules on the energy performance of buildings. During the talks the "whole text was open for discussion", as MEPs and governments have yet to define their negotiating positions, according to one source.

Negotiations are scheduled to continue next week and again in mid-November. But MEPs have already requested further talks, suggesting a deal is unlikely before the end of November at the earliest.