There is currently very heavy traffic as police are responding to an 'ongoing' incident on the M25.
A spokesperson for Hertfordshire Police said: "Police were called shortly after 3.30pm today (April 4) following an incident at junction 23 of the M25 clockwise.
"It was reported than a man had been assaulted on the slip road.
"Officers and paramedics are currently in attendance."
One motorist described the traffic as 'gridlocked' in Potters Bar.
Hertfordshire Highways said: "There is very heavy traffic at Potters Bar B556 Mutton Lane, traffic is currently diverting off the M25 due to a police incident."
National Highways confirmed that the lanes of the M25 have now reopened.
"Traffic has been released and all lanes are now open on the M25 in both directions within J23 following an earlier incident.
"There are residual delays of approximately 40 minutes in both directions."
For the most up-to-date information about the county's roads, visit our LIVE Hertfordshire traffic map.
Join our Hertfordshire Travel Information group on Facebook for all the latest traffic news in Hertfordshire.
Do you have a live or breaking news story from across Hertfordshire? Email: hertslivenews@archant.co.uk
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