IAG yesterday urged EU competition regulators to clear the takeover of its loss making Heathrow rival from Lufthansa.
The deal would boost IAG’s share of slots at the London hub from 43% to 52% and allow it to launch lucrative new long-haul routes.
But rival and failed bidder Virgin Atlantic has urged anti-trust regulators to veto the deal, saying it would harm competition and push up prices.
A spokesman said: “It is vital that both the Commission and the Office of Fair Trading give the fullest possible scrutiny to this deal and ensure that it is stopped.”
It is due to submit evidence to the EU this week.
EU Competition Commissioner Joaquin Almunia last year blocked the merger of Greece’s Aegean Airlines and Olympic Airways because he considered it would have resulted in higher prices for consumers.