London Heathrow has warned that a return to pre-Covid demand is likely to take “a number of years”, as the airport prepares to lift its current cap on passengers.

Heathrow shrugged off strikes and wintry weather to get 5.9 million passengers through its terminals last month.

However, that is down 12 per cent on the London airport’s Christmas and new year flights in 2019 when it handled 6.7 million, a record for December.

The long haul back to normality is taking time: domestic passenger numbers are down by nearly a third, or 1.5 million a year, from pre-pandemic levels, while the long tail of Covid-19 in China has halved Asia Pacific traffic.

In 2022, which was blighted by staff shortages, Heathrow handled 61.6 million passengers, down 24 per cent on the record 80.9 million of 2019.

John Holland-Kaye, chief executive, said “2022 ended on a high”, referencing the work done to mitigate the impact of industrial action by Border Force and terminal and baggage staff.

The airport stated: “Forward planning and close collaboration with airport partners ensured we provided a smooth and efficient service to travellers throughout the festive period.”

The 1.45 million passengers on North American routes last month is only 6 per cent shy of 2019’s performance.

The fastest-recovering sector for 2022 as a whole is Middle Eastern routes, which with 6.94 million passengers was just 10 per cent short of 2019.

Asia Pacific routes continue to suffer heavily, weighed down by the ongoing Covid-19 situation in China. The 713,000 passengers last month is down 25 per cent on pre-pandemic levels, with the total for the year more than halved to 5.5 million from 11.4 million.

UK domestic passenger numbers are struggling to recover, too: the 324,000 people who travelled through Heathrow last month is down 18 per cent on its pre-pandemic performance, and the year’s total is 31 per cent shy of 2019 figures at 3.3 million.

In data reported by Cirium, the aviation consultancy, Heathrow is falling behind European counterparts in connectivity, that is the number of individual routes an airport flies to and from.

Frankfurt is top with 330 different airports served globally. Paris Charles de Gaulle and Amsterdam Schiphol come in 3rd and 4th, behind Istanbul.

Heathrow is eighth with 242 connected airports, behind Chicago O’Hare, Dallas Fort Worth and Dubai. Heathrow connects to only 29 more airports than its rival Gatwick, 15th.