Up to 2,500 people were moved to safety after a fire at a building site in north-west London.
The fire started in an empty block of flats
Hendon Police Training College, a police station, a student halls of residence and a number of homes near the blaze in Colindale were evacuated.
About 100 firefighters took five hours to put out the fire, which started on Wednesday afternoon in a block of flats that was under construction.
An investigation by police and the fire brigade is under way.
A section of the A41 Watford Way was closed for two hours as high-pressure hoses were laid across the road.
A spokesman for developers St George Plc said they were grateful for the efforts of the firefighters involved, but would wait for their report before making any further comment.
A cordon has been put in place around the area as gas cylinders are thought to be involved, but no-one was injured.
The fire took hold at two of the buildings under construction - but also affected a nearby halls of residence building for Middlesex University.
The halls and homes on Graham Park Estate were evacuated.
One of the halls was so badly damaged by fire that students have not been able to return.
A spokeswoman for the university said it was fortunate graduation was over and there were only 150 students on their 576-capacity Hendon campus.
Aerodrome Road remains closed. Colindale police station was closed on Wednesday but reopened by Thursday.