“This is a huge blow to UK competitiveness as many long-haul routes, which are highly important to the UK’s economy, exports and wider connectivity, rely on transit passengers,” it said in an update.

In November, the UK government started the Electronic Travel Authorisation (ETA) for Qatari nationals travelling to the UK from Qatar. But the fee resulted in a decrease in passengers from the Gulf country at Heathrow.

It is expected to be applied to other overseas travellers throughout 2024.

The ETA is akin to the US Electronic System for Travel Authorization system and requires travellers to apply to enter the country before departing and pay a £10 fee.

This applies not only to direct flights from the country but also for those who are using UK airports for more than two hours to connect to other flights.

“With more connecting passengers expected to choose other hubs as the scheme expands, minsters need to take action to remove this measure,” the airport said.