Part of Stansted had to be evacuated in the early hours of this morning after a fire in one of its passenger lounges.
The airport stopped passengers from passing through security until reopening at 6am.
Flights are departing and first arrivals of the morning have landed but some delays are likely as a knock-on effect of the earlier issue, according to an airport spokesperson.
In an update posted on X, the airport said: “Following the partial evacuation caused by a fire in our Escape Lounge, security has now been reopened.
“Due to the number of passengers in the area, it may take longer than usual to pass through and we apologise for any inconvenience.
“Please check the status of your flight with your airline.”
Stansted added: “We thank passengers for their patience as we worked with the emergency services to ensure the terminal was safe to fly reopen.”
An investigations has begun but the cause of the fire remains unknown.