Heathrow Airport has introduced a cap on passenger numbers this summer as the aviation sector struggles to cope with demand for travel.
No more than 100,000 daily passengers will be able to depart from July 12 until September 11, the west London airport announced.
Airlines planned to operate flights with a daily capacity averaging 104,000 seats over that period, according to Heathrow.
Heathrow Airport has introduced a cap on passenger numbers this summer Steve Parsons
Heathrow chief executive John Holland-Kaye Yui Mok
The airport said it has ordered airlines to “stop selling summer tickets to limit the impact on passengers”.
Heathrow Chief Executive Officer John Holland-Kaye said: “Over the past few weeks, as departing passenger numbers have regularly exceeded 100,000 a day, we have started to see periods when service drops to a level that is not acceptable.”
Problems include long queue times, delays for passengers requiring assistance, bags not travelling with passengers or arriving late, low punctuality and last-minute cancellations, Mr Holland-Kaye said.
He said this is due to a combination of poor punctuality of arrivals due to delays at other airports and in European airspace, as well as increased passenger numbers “starting to exceed the combined capacity of airlines, airline ground handlers and the airport”.
He added: “Our colleagues are going above and beyond to get as many passengers away as possible, but we cannot put them at risk for their own safety and wellbeing.”