West Sussex Fire and Rescue say the M23 northbound continues to be closed between Junction 10 for Crawley and Junction 9 for Gatwick due to a crash.
The closure, which started early this morning, is expected to remain in place for several hours.
Drivers are being urged to avoid the area and find alternative routes where possible.
A spokesperson for WSFRS said: "The M23 northbound is currently closed between Junction 10 for Crawley and Junction 9 for Gatwick Airport following a road traffic collision involving one vehicle.
"Joint Fire Control was alerted at 5.06am and mobilised two fire engines and a heavy rescue tender to the scene.
"The road is expected to remain closed for some time.
"Drivers are urged to avoid the area, and those heading to Gatwick Airport should use alternative routes."
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