Firefighters were called to assist at the partial collapse of a roof in Brent Street in Hendon.
A brick fascia approximately 20 metres long above a row of shops collapsed to ground level. There are no reports of any injuries.
Five people were evacuated before the arrival of the Brigade and firefighters evacuated a further 15 people as a precaution.
The Brigade was called at 12.49pm and the incident was over for firefighters at 13.5pm. Two fire engines from Hendon and Finchley fire stations attended the scene.