A brick tower collapsed into the roof of the sports hall next to it at a school site in Brent Park.
Firefighters were called to the school, which has not been named, on Brentfield Road just before 12.30pm yesterday - June 12.
Firefighters used thermal imaging cameras to assist in carrying out a search of the single-storey sports hall.
A 25-metre cordon was put in place as a precaution while crews worked to make the scene safe for an hour-and-a-half.
There were no reported injuries.
One fire engine from Park Royal and two fire rescue units from Heston and East Ham fire stations attended the scene.
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