Storm Eunice: Fallen tree blocks several lanes on M25
The tree was blocking the carriageway between junction 19 for Watford and 20 for Kings Langley/A41.
Cars took to the narrow lanes to bypass the congestion.
National Highways says there is currently 7.3 miles of congestion on the approach, causing delays of 35 minutes above usual journey times.
The incident was being cleared at around 3pm.