The largest airline group operating at Heathrow Airport is leading efforts to appoint an independent adviser to scrutinize the airport’s construction and expansion plans, amid growing concerns over rising costs. International Airlines Group (IAG), owner of British Airways, Iberia, Aer Lingus, and Vueling, along with the Heathrow Airline Operators Committee (AOC), representing over 90 carriers and ground handlers, has invited firms to tender to provide an independent cost and value-for-money review.

This initiative comes as Heathrow seeks planning permission for its £49 billion third runway project, a scheme at the center of disputes over its pricing and cost management. Airlines have expressed frustration with existing oversight mechanisms, including the Civil Aviation Authority’s (CAA) supervision and airport-led panels meant to offer “real-time” project scrutiny, which operators believe lack sufficient independence and credibility.

The call for an independent review reflects airlines’ concerns about the escalating costs at Heathrow, which is already regarded as one of the world’s most expensive airports. A report commissioned by the CAA and prepared by consultancy Steer found that a sample of 13 projects at Heathrow had experienced a 61 percent cost increase, from an original estimate of £943 million to £1.52 billion. Projects cited include upgrades to key airport tunnels and the £127 million acquisition of Heathrow’s Compass Centre head office.

Despite the sharp increases, Steer’s report concluded that only £5.7 million of £842 million spent during the review period was “demonstrably inefficient and wasteful,” suggesting limited scope for cost recovery. This finding angered airlines, with Nigel Wicking, chief executive of the AOC, condemning the conclusion as effectively granting Heathrow a “blank cheque.”

In response, Heathrow has defended its spending, emphasizing that all investments are pre-approved by its airline customers and rigorously reviewed by the CAA. The airport noted that its latest internal review found that over 99 percent of recent expenditures were efficient.

The prospective independent adviser is expected to provide more rigorous oversight than traditional quantity surveying or cost validation. According to the tender documents, the adviser will be required to assess not only whether cost estimates are reasonable but also the necessity of investments, how they compare to benchmarks, whether objectives might be achieved through alternative means, and the broader implications for airport charges.

More than 50 consultancy, accounting, banking, and legal firms, including Aecom, Mott MacDonald, Arup Group, Alvarez & Marsal, Deloitte, PwC, KPMG, Lazard, and Ashurst, have been invited to submit expressions of interest in the role.

The airlines’ push for external scrutiny underscores ongoing tensions over Heathrow’s expansion costs and the potential impact on airline charges, with airport users seeking greater assurance that the substantial investments will deliver value for money without imposing undue financial burdens.