The clockwise M25 was closed as police responded to "concerns for someone’s welfare".

Hertfordshire Constabulary confirmed officers shut the M25 today (February 21) “as a precaution” between junctions 18 and 20, near Watford.

Four miles of traffic and approximately half an hour of delays built on the stretch as it was closed for around 20 minutes at 5pm.

All lanes have now reopened, according to National Highways.

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While the closure was in place, anticlockwise traffic was being diverted via the exit/entry slip roads to leave the motorway and then later re-join the M25 at J18.

National Highways described the closure as being due to a “Herts Police-led incident”.

A force spokesperson then confirmed officers were dealing with the "concern for welfare incident" near junction 18.

As of 5.45pm, Google Maps is now showing only around 10 minutes of delays.

Hertfordshire Constabulary has been contacted for more information. Updates to follow.