The A315 London Road in Hounslow is closed in both directions after a crash, with drivers warned of heavy traffic in the surrounding area.
The road is shut between Kingsley Road and Bridge Road. A diversion is in place while the incident is dealt with.
Eight bus routes are affected: the 117, 222, 235, 237, 281, E8, H22 and H37. Passengers using those routes should expect delays and possible diversions until the road reopens.
Drivers heading through Hounslow, including those travelling towards Heathrow, are advised to check their route before setting off and allow extra time for their journey.
Details of what caused the crash, and whether anyone was hurt, have not yet been reported. No reopening time has been given.
This article will be updated when the road reopens or more information becomes available.
It is the latest in a series of road closures affecting London drivers this week. In Sutton, a man was taken to a major trauma centre after a crash closed Stonecot Hill, while a vehicle fire closed the A204 in Tulse Hill with three bus routes diverted. Separately, parents in Sutton have demanded action over 213 bus delays affecting schoolchildren.
