Firefighters battled a mammoth blaze near St Albans this afternoon after a lorry carrying cooking oil and food overturned and caught fire.
Emergency services and engineers were also called to the M25 junction 21a following the incident at around 1.30pm.
An investigation has been launched and the road is currently expected to be closed for several hours, including during rush hour.
The Highways Agency advised drivers to allow extra travel time in the wake of the accident.
They added that road users wishing to use the M25 anti-clockwise should exit the M25 at junction 23 and take the A1(M) north, exit at junction 3 and join the A414 west.
Then take the A405 south and rejoin the M25 at junction 21. For more information visit www.highways.gov.uk/traffic
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here