The road is not expected to fully reopen until after the evening rush hour at the earliest.
A clearly signed diversion is in place via the A4, A4155 and A33 to rejoin the M4 at junction 11. Long distance traffic approaching junction 13 eastbound is encouraged to use the A34 southbound, A303 eastbound and M3 eastbound.
Drivers planning to use this section of the M4 are advised to plan their journeys and allow extra time to reach their destinations.
Members of the public should contact the Highways England customer contact centre on 0300 123 5000.
Journalists should contact the Highways England press office on 0844 693 1448 and use the menu to speak to the most appropriate press officer.