The London Fire Brigade dispatched firefighters to tackle a large blaze at an electrical substation in Hayes, near Heathrow, late on Thursday.
“This is a highly visible and significant incident, and our firefighters are working tirelessly in challenging conditions to bring the fire under control as swiftly as possible,” said assistant London Fire Brigade commissioner Pat Goulbourne.
“This will be a prolonged incident, with crews remaining on scene throughout the night. As we head into the morning, disruption is expected to increase, and we urge people to avoid the area wherever possible.”
A 200-metre cordon has been established around the area and about 150 people have been evacuated, according to the fire service.
The fire brigade added that the cause of the fire was not known.
