Heathrow Airport has recorded its busiest month since the start of the coronavirus pandemic.

The airport said it was used by 4.2 million passengers in March.

This represents nearly an eight-fold increase on the total during the same month in 2021.

READ MORE: Business employees join Heathrow Airport 'meet and greet' feud as parking chaos continues

A spike in coronavirus-related staff absences, combined with difficulties finding and passing security checks for new recruits, means the aviation sector has struggled to cope with the number of people flying in recent weeks.

Heathrow admitted “resources are stretched” but described how it is “working closely with airlines and ground handlers to make sure this increase in demand can be met while keeping passengers safe”.

Chief executive John Holland-Kaye said: “It is fantastic to see the airport coming back to life after two years, and I want to thank all team Heathrow colleagues for working together to serve our passengers.

“Everyone at Heathrow is doing everything we can to make sure passengers get on their way as smoothly and safely as possible.”

The rise in passengers was attributed to the Government’s removal of all coronavirus travel restrictions.

Demand was driven by outbound leisure travel at weekends and during school holidays.

There is “congestion in check-in areas at peak times” as “half of global markets” still require passengers to pass coronavirus checks such as testing and vaccination status, according to Heathrow.

Departing passengers are advised to check with their airline to confirm when they should arrive at the airport.

ALSO READ: All the jobs being advertised by Heathrow Airport - and how much they'll pay

Heathrow added that “other airport processes are currently working to plan” and it is working with Border Force to “ensure sufficient levels of resource are in place to cope with the large number of passengers returning to the UK over the next couple of weeks”.

Meanwhile, new figures show Heathrow slipped from the second busiest airport for international travel before the pandemic to number seven in 2021.

Airports Council International said Heathrow was used by 17.6 million international passengers last year, down 77% on the total for 2019.

Dubai maintained its spot at the top of the ranking.

The five airports to overtake Heathrow in 2021 were Istanbul, Amsterdam, Frankfurt, Paris Charles de Gaulle and Doha.