IAG chief executive Willie Walsh has called for the government to break up Heathrow’s “monopoly” by letting independent operators run the airport’s terminals.

“Heathrow’s had it too good for too long and the government must confirm the CAA’s powers to introduce this type of competition,” said Walsh. “This would cut costs, diversify funding and ensure developments are completed on time, leading to a win-win for customers.”

But Heathrow’s chief executive John Holland-Kaye accused IAG, which currently holds 54% of Heathrow’s slots, of trying to stifle competition.

“This is a blatant attempt by Mr Walsh to maintain a dominant monopoly for BA at Heathrow and to frustrate the increased airline competition that should result from expansion,” he said.

Holland-Kaye told MPs this week that he was “increasingly confident” that Heathrow passenger charges could be “kept close to the current level”, despite the £14 billion cost of the third runway. Although he said he could not “guarantee” this.

“It’s not just about landing charges, we should also be concerned about the price passengers pay for tickets,” he added. “With more competition the price will come down.”

BA’s arch-rival Virgin Atlantic agreed with Walsh that Heathrow’s “track record of delivering capital projects on time and on budget is not good enough”.

But a Virgin spokesperson added: “What he [Walsh] fails to mention is that IAG operates more than half of Heathrow’s slots, so many routes that are only served by one of his airlines. Expansion must deliver a significant increase in airline competition.”

The House of Commons is due to vote on Heathrow expansion during the first half of 2018.