A stretch of the A41 is closed in both directions.
The road is shut between two roundabouts near Elstree because of a burst water main.
There is no access either way between the Esso roundabout, near Centennial Park, and the A411 Elstree Road.
ROAD CLOSED: #Elstree A41 currently CLOSED BOTH WAYS between A411 Elstree Rd and A5183 Elstree Hill South. Expect heavier traffic on other roads in the area because of this. #AvoidTheQ pic.twitter.com/qZIVBqUT9T
— HCC Highways (@Herts_Highways) January 2, 2020
Affinity Water has been on site since yesterday after drivers reported flooding in the road.
The water main burst in the very early hours of New Years Day.
Drivers can divert via Elstree Road/Watford Road and Elstree Hill South, to bypass the closure.
The road may not open again until Monday January 6.
A statement from Affinity Water on Twitter says: "We are repairing a burst on A41 North Western Avenue, Bushey Heath.
"To complete the repair work safely, we require road closure. This may cause traffic delays for road users. We aim for the road to be accessible by 06/01. We are sorry for any inconvenience caused."
Traffic is coping well at the moment, but delays can be expected.
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