Around 20 injured after Heathrow Airport terminal evacuated over 'hazardous materials' concerns

Terminal 4 check-in shut and members of the public were urged to avoid travelling to the terminal as specialist crews respond to the incident.

Despite the injuries, "no trace of any adverse substance was found" after officers were called to Heathrow, the Metropolitan Police has said.

In a post on X, the airport said: "Emergency services have confirmed Terminal 4 is safe to reopen and we are doing everything we can to ensure all flights to depart as planned today.

"We are very sorry for the disruption caused, the safety and security of our passengers and colleagues is our number one priority.

"We encourage passengers to check with their airline for the latest information about their flight this evening and our colleagues will be on hand into the night to assist."

Management were seen in social media clips telling travellers they would be allowed back into the building.

London Fire Brigade said in a statement: "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.

"The brigade was first called about the incident at 17:01, and crews from Feltham, Heathrow, Wembley and surrounding fire stations have been sent to the scene."

Pictures shared online appeared to show multiple ambulances, fire crews and police outside Terminal 4.

Transport Minister Heidi Alexander said: "Emergency services are responding to an incident at Heathrow’s Terminal 4 which has prompted its evacuation.

"I’m monitoring updates from those on the scene, as well as Heathrow Airport itself. Passengers should not travel to Terminal 4 until advised otherwise."

National Rail said trains stopped calling at the terminal due to "emergency services dealing with an incident".

Most flights have not been cancelled but travellers encouraged to allow extra time for their journeys.

According to the airport's website, 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.

Footage posted on social media showed passengers with their luggage waiting outside the airport, with some wrapped in foil blankets.