The M4 is closed in both directions between junctions 19 and 18 near Yate after a crash, leaving drivers facing delays of more than 45 minutes.
Emergency services are at the scene dealing with the incident, according to National Highways. Around four miles of congestion has been reported on the approach to the closure.
Diversion route to be announced
Motorists are being urged to plan ahead, with a diversion route due to be announced. The motorway remains shut while crews continue their work.
Drivers are advised to expect lengthy delays and to consider alternative routes if possible.
Live updates ongoing
This is a live blog and more details are expected to follow as the situation develops.
