A car went up in flames between junction 15 (M4) and junction 16 (M40) near Uxbridge on Wednesday (August 2).
The fire occurred around 1.30pm and blocked the motorway, with crews from Royal Berkshire Fire and Rescue Service attending to put out the fire.
Highways England tweeted at 1.36pm to say: "M25 clockwise J15 - J16 is blocked due to a car fire. Delays are building on approach. Emergency services on the way."
It later added: "M25 clockwise J15 - J16 is blocked due to a car fire. RBFRSofficial Fire crews are on scene dealing."
One lane opened just before 2pm, with all other lanes reopening at 2.24pm.
The fire had a major knock-on effect on traffic past the scene in both directions.
Clockwise tailbacks were back past Egham to junction 12 for the M3 and there was heavy traffic anticlockwise past the scene.
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