Two people were taken to hospital after a vehicle fell down an embankment.
Emergency services were called to the M1 exit slip road at junction 5 for Watford at 11.30pm on Sunday.
A vehicle had been travelling northbound when it got off the carriageway at Watford before crashing through a barrier and falling off the road.
The vehicle came to a rest on its side in a wooded area.
Inside the vehicle was a dog who was taken to an emergency vet but was thankfully uninjured.
Fire crews from Garston, Watford, and Borehamwood attended. Hertfordshire Constabulary say the injuries sustained by the two people in the car were not life threatening. The East of England ambulance service has been approached.
The vehicle was recovered and police left the scene at 3am but the slip road was not opened until after 5am on the Monday morning.
Nearly 24 hours later, police were called to an overturned car on the M1 northbound between junctions 4 and 5. The whole road was blocked while traffic officers dealt with the incident. One lane was then opened at around 9.30pm to allow some traffic to pass.
The M1 was blocked after a vehicle overturned. Credit: Highways England
The carriageway was clear by 11pm.
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