An eye witness, Sophie Burnett said:
"The fire began around 12 o'clock, they began by shutting the shops closest like Boots and M&S, they then evacuated the whole of North Terminal Landside and have stopped all publicly transport coming over to the terminal including the shuttle and the public bus services.
"They're currently trying to isolate the smoke from the building."
More top news
Thursday's weather for the east of the region
Foreign Office Minister Tobias Ellwood has been praised after attempting to save the life of the police officer killed in New Palace Yard.
Some clearer periods at first tonight, before further outbreaks of rain return westwards.