Willie Walsh, the former chief executive of British Airways owner IAG who now runs airlines group Iata, said last month the decision raised significant concerns on the wider process the Civil Aviation Authority is conducting for deciding Heathrow’s charges in the longer term.

“We are not confident that the CAA is prioritising the needs of consumers, nor is it considering the wider implications of Heathrow’s growing uncompetitive position as a global air hub. It is essential that the [Transport] Secretary intervenes to remind the CAA of its obligations.”

A Heathrow spokesman responded: “The CAA’s flawed analysis assumes that operating costs at Heathrow next year will be £173m lower than our budget. This is even lower than we were able to achieve in 2020, when we served half as many passengers with only one runway and two terminals operating and the benefit of a government furlough scheme.

“Uncorrected, this risks leaving Heathrow without sufficient cash flow to support investment in improving passenger service and resilience.”

Heathrow’s justification for increasing its landing charges is based on forecasts that demand for air travel will remain depressed for a number of years. 

Fewer passengers means prices must go up for the airport to balance the books, Heathrow claims, but pleas to increase charges by up to 90pc were rejected. 

Before the pandemic, passenger numbers typically rose year-on-year. The airport welcomed almost 81m people in 2019. 

The 2021 passenger numbers are worse than those for 2020, although this included three months of the year where traffic was comparatively normal. 

The last time Heathrow welcomed fewer passengers was in 1972, when 18.3m people travelled from the airport.