Ten fire engines and around 70 firefighters responded to an incident on Watford Way, Mill Hill.
The fire was located in a range of commercial properties with flats above. One of the Brigade's 32m ladders was deployed to the scene as part of our response.
Part of the nearby A1 was closed in both directions as crews responded.
The Brigade received the first of 13 calls reporting the fire at 0046, and Control Officers mobilised crews from Mill Hill, Hendon, Finchley and surrounding fire stations to the scene. The incident was under control by 0316.
The cause of the fire is under investigation..