The fire brigade has said that an electrical fault at the top of the Obel tower caused the building’s roof to catch fire.
Roughly 50 crew members were at the scene at around 7.30pm, plus nine fire vehicles.
There were no visible signs of fire and no smoke by that stage.
Only one floor – the 27th at the very top – was evacuated.
There were a handful of bystanders waiting around in the cold to access the building.
Lee Hamilton, 24 and working as a consultant, said he had been waiting for around 45 minutes to get to his car, but was not very clear on what was happening.
He said: “I’d say it’s probably a good thing the police are keeping it under control, and the fire response was so quick. But on the other hand, I can’t get my car and I’m stuck here.”
Another, Anna Black, 21, said that she had likewise heard very little, and was anxiously awaiting contact from her sister who lives on the fourth floor from the top.
The incident was declared over at about 9pm, and there were no reports of any injuries.
The call to the emergency services had been put in at 5.50pm.
At midnight on Friday, group commander Lenny Entwistle said it had been caused by high-voltage electrical cables on the roof, which ignited roughly 23 square metres (270sq ft) of roof panelling.
He said the electrical cables were connected to the lighting system which gives the uppermost portion of the building its blue-ish hue.
According to property consultancy firm Savills (and security firm Honeywell), the 85m (279ft) structure is the tallest skyscraper on the whole island, north or south.