Virgin Atlantic Chairman Richard Branson seeks to “challenge every aspect“ of the European Commission’s (EC) approval for International Airlines Group (IAG) to take over rival BMI from Lufthansa. In the British newspaper The Telegraph, Branson wrote that the decision would “damage the British airline industry for years to come. However you look at the likely outcome of the BA purchase of BMI, you cannot find anything other than a serious erosion of competition at London Heathrow, leading to the consumer paying dearly.”

The EC approved the takeover with some conditions: IAG has to relinquish 12 daily slot pairs at London Heathrow Airport for competitors to be used on a defined set of routes on which new entrants are expected to uphold competition. Following the completion of the transaction this month, IAG unit British Airways will hold about 54% of the slots at Heathrow including the 8.5% that have been controlled by BMI. Virgin Atlantic has 3%.

If Virgin Atlantic’s appeal is rejected, Branson vows to lobby strongly for the 12 slot pairs to be allotted to one airline. “The slots cannot be broken up among numerous airlines—that would merely be another gift to BA,” Branson emphasizes. “You cannot provide serious competition in a piecemeal way.”

Branson admits that IAG CEO Willie Walsh was correct in assuming that it “must be galling” for Virgin Atlantic to have to use its competitor to feed it passengers: “He is right. It is.”