Ten fire engines and around 70 firefighters tackled a fire at a church on South Road in Southall.
At the height of the fire, most of the ground floor, second floor and roof were alight.
South Road remains closed in both directions between Park Road and High Street and the Brigade is continuing to advise the public to avoid the area.
Two of the Brigade's 32-metre turntable ladders were deployed to the scene to help fight the fire from above.
Control Officers took the first of over 20 calls at 2130 and mobilised crews from Southall, Ealing, Heston and surrounding fire stations to the scene. The fire was under control by 0038.
The cause of the fire is under investigation.