The westbound carriageway has been closed since 7.10am (credit: Google Maps)
Emergency services remain at the scene on the westbound carriageway, just before the M25 junction, after the collision happened at around 6.45am.
Two people with serious injuries were transported to the Queen’s Hospital in Romford.
The road remains closed between North Stifford and Lakeside.
A diversion is in place from the carriageway on the A1012.
Police remain at the scene.
A spokesperson from Essex Police said: “We would like to thank motorists for their patience and understanding while we deal with this incident.”
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Tags: Grays, Thurrock