Emergency services were called to reports of an incident at the airport at around 5pm today (September 8).
In a post on X, the airport advised passengers not to travel to the terminal as the incident is being dealt with.
A spokesperson for London Fire Brigade said: “Specialist crews have been deployed to carry out an assessment of the scene, and part of the airport has been evacuated as a precaution whilst firefighters respond.”
National Rail said trains were not calling at Heathrow Terminal 4 due to “emergency services dealing with an incident”.
Flights from the affected terminal are still scheduled to depart on time, with only one delay to a Saudia airline flight to Jeddah in Saudi Arabia currently expected, according to the airport’s website.
This is a breaking news story. More to follow.