Heathrow airport has argued “the case for expansion has never been clearer” after it lost its position as Europe’s busiest airport to Istanbul.

Figures published on Tuesday showed 7.86 million passengers passed through Heathrow’s four terminals in July,whereas its Turkish counterpart recorded 8.15 million passengers over the same period.

Annual figures from the trade body Airports Council International show Heathrow was Europe’s busiest airport from 1996 to 2019.

The UK’s biggest airport, located west of central London, lost that position in 2020 amid coronavirus travel restrictions before regaining it in 2023 and holding the title since then.

Heathrow’s July passenger total was 1.5% down compared with the same month last year, whereas Istanbul saw a 2.3% boost.

The US-Israel war on Iran has had an impact on Heathrow’s passenger traffic.

Its passenger numbers on Middle East routes in July were down 20.2% year on year.

Despite this, Heathrow continues to operate its two runways at near full capacity, and is seeking government permission to build a third.

An expansion proposal by the airport’s owners would enable it to accommodate 150 million passengers per year. It recorded 84.46 million passengers in 2025.

Heathrow said: “Heathrow is operating at capacity. The case for expansion has never been clearer, as Heathrow was overtaken in July by Istanbul airport as the busiest hub in Europe.

“Our plans will ensure the country gets the infrastructure it needs to stay competitive and will deliver all-important economic growth.”

The transport secretary, Heidi Alexander, launched a consultation on the renamed Heathrow expansion national policy statement in June, setting out the conditions needed if the project is to be given the go-ahead.

The then chancellor, Rachel Reeves, said at the time she was determined to get “spades in the ground” for the third runway in the current parliament, and for it to be built by 2035.

Andy Burnham, who sacked Reeves, has previously expressed concerns over Heathrow expansion, stating the plans divert infrastructure investment “away from the north and traps it in London”.

Heathrow said 19 July was its busiest day of the year so far after many schools broke up for summer, with 267,000 passengers recorded.

It added that several new airlines began serving the airport last month, which demonstrates “clear demand for access to Heathrow”.

They include ITA Airways from Italy, Alaska Airlines from the US and Riyadh Air from Saudi Arabia.

The Heathrow chief executive, Thomas Woldbye, said summer was “off to a flying start” but “we want to go further” by “growing our route network and passenger offering”.

He continued: “Expanding Heathrow will help ensure the UK remains home to Europe’s leading hub and continues to benefit from the trade, investment and tourism that increased connectivity will bring.”