The airport claimed the number of people employed in ground handling has "fallen sharply" over the last two years as airlines cut costs during the pandemic.

"We have been raising our concerns over lack of handler resource for nine months," a Heathrow spokesperson said. "We estimate airline ground handlers have no more than 70% of pre-pandemic resource, and there has been no increase in numbers since January.

"In the second half of June, as departing passenger numbers regularly exceeded 100,000 a day, we started to see a worrying increase in unacceptable service levels for some passengers; an increase in delays to get planes on to stand, bags not travelling with passengers or being delivered very late to the baggage hall, low departure punctuality and some flights being cancelled after passengers had boarded."

The airport said it applied a cap on departing passenger numbers to protect consumers after demand began to exceed the capacity of airline ground workers. It claimed ground handler performance has been "much more stable" since the cap was introduced.

It also said it began ramping up its own operations in November 2021, and encouraged airlines and their ground handlers to do the same.

"Planning has been based on summer peak demand exceeding 85% of 2019, broadly in line with actuals," the spokesperson added. "All parts of the airport are now fully operational."

The airport has hired 1,300 new staff members in the last six months and predicts it will have a similar level of security resource by the end of July as pre-pandemic.

In the six months up to 30 June 2022, Heathrow’s adjusted loss before tax reduced by £466m to £321m as a result of higher passenger numbers and higher aeronautical charges offset by increased costs.

The airport also criticised the CAA’s H7 Final Proposal, saying it will "deliver worse outcomes for passengers" by focussing on cost cutting to improve airline margins when "it should be rebuilding capacity, with a focus on safety, consumer service, resilience and efficiency".

Heathrow chief executive John Holland-Kaye said the airport’s summer getaway has "started well" thanks to "early planning" and keeping demand in line with airline ground handler capacity.

"We can’t ignore that Covid has left the aviation sector deeply scarred, and the next few years will need investment to rebuild capacity, with a focus on safety, consumer service, resilience and efficiency," he added.

"Airlines need to recruit and train more ground handlers; airports need catch up on underinvestment during the Covid years – at Heathrow, that means replacing the T2 baggage system and new security lanes. Recent months have shown that passengers value easy, quick and reliable journeys, not penny pinching, and the CAA should be encouraging the investment that will deliver for consumers."