Emergency services are currently dealing with a vehicle alight on the busy M25 near to Junction 23 and Junction 24 (A1(M) J1/A1/A1081 South Mimms Services.
The road is closed eastbound due to a collision. The A1 Barnet Bypass is slow southbound between the M25 Junction 23 to the A1 Watford Way.
Fire crews and Police were called just after 6pm during the busy hour after the vehicle became engulfed in flames.
It is not currently clear if anyone has been hurt.
There are very long delays on approach to the incident with traffic currently being held by officers form Highways England
A spokesman for Highways England Said:
The M25 in Hertfordshire is closed clockwise between J23 (South Mimms) and J24 (Potters Bar), due to a HGV fire.