A “large vehicle” fire saw the northbound M1 closed last night.
Emergency services rushed to the incident between junction eight and nine, for Hemel Hempstead and Redbourn, at about 10.50pm.
At one point, there was more than two miles of congestion building up behind the fire, making at least half an hour of delays.
A picture Tweeted by Herts Fire and Rescue Service seemed to show flames engulfing a car transporter.
HFRS advised drivers to avoid the area, later Tweeting: "Four vehicles were saved from fire damage thanks to @Hemel_RedWatch on the M1 last night."
Two lanes were reopened at about 12 midnight.
More information on this as it becomes available.
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