The M25 is closed in both directions in Hertfordshire because of a lorry fire and smoke blowing across the carriageway.
The section affects is between junction 21a for London Colney and junction 23 for South Mimms and the A1(M).
The Highways Agency says the road is expected to re-open from 3:00 pm.
More top news
Meet Tuesday's finalists in the Anglia region for the Pride of Britain Awards.
Essex part-timers to visit League Two promotion chasers Exeter in the First Round
In the first of three special reports, our Sports correspondent Donovan Blake looks at how sports are changing - first our need for speed.