Eight fire engines and 58 firefighters and officers tackled a fire on the ground floor of a London Metropolitan University complex on Holloway Road.
The whole of an IT server room on the ground floor was damaged by fire but fire crews prevented the blaze from spreading to adjacent rooms.
Station Manager Richard Arnold said:
"Firefighters located a fire in an IT room on the ground floor. Thankfully no one was involved but the University have confirmed that lessons in the Tower complex and enrolment will be suspended today."
The Brigade was called at 0549 and the fire was under control by 0951. Fire crews from Holloway, Islington, Kentish Town, Soho and Stoke Newington fire stations were at the scene. The cause of the fire is under investigation.