The M25 has re-opened in Kings Langley following emergency bridge repairs - but Highways bosses have warned motorists to expect more closures tonight.
The anticlockwise road closed this morning between Junction 21a and Junction 20 after a routine inspection found an isolated crack on a small section of the structure underneath the carriageway.
This viaduct carries the M25 over the railway, Station Road, the River Gade and farmland.
The road will need to close again tonight from 10pm to 5am tomorrow while Highways England completes the repair.
A Highways England spokesman said: “Safety is Highways England’s top priority. During a routine inspection yesterday a minor crack was discovered on the Gade Valley Viaduct near to the M25 junction 20.
“The closures have been in place to allow repairs to be carried out as quickly as possible to stop the crack from growing and maintain safe journeys. We would like to thank drivers for their patience over the last 24 hours.”
For tonight’s closure, the anti-clockwise M25 will be closed between junctions 21a and 20 with a clearly signed diversion following the square symbol via the A405 and A41. Drivers wishing to travel onto the northbound M1 will be diverted via the A405 and A414.
Traffic from the southbound M1 onto the anti-clockwise M25 will be filtered down into one lane and diverted off at the M25 junction 20 to use the roundabout and re-join the M25.