The A120 in Essex has reopened more than three hours after a crash involving a horse box trailer left a motorist in Addenbrooke’s Hospital.

Emergency services were initially called to reports of a “serious” multi-vehicle collision involving a car towing a horse box trailer and a heavy goods vehicle on the A120 eastbound near Great Dunmow at around 5.40pm on Sunday evening.

The two horses do not appear to have been injured, an Essex Police spokesman said. The road reopened at around 9pm.

The force spokesman said the driver of the car, a man, was taken to Addenbrooke’s Hospital in Cambridge with a head injury not believed to be life-threatening or life-changing. He said it was for pre-cautionary reasons.

A fire brigade spokesman said: “Crews were called to a road traffic collision on the A120 between Stansted and Dunmow involving two vehicles, one of which was carrying two horses.

“On arrival firefighters reported that one man was trapped in his vehicle and that two horses were trapped in the horsebox, which was still on all four wheels.

“Firefighters worked to release the man from his car and left him in the care of the Ambulance Service.

“(Our) animal rescue unit worked with a vet and the horses’ owner to assess the condition of the animals and released them into the care of the vet at 7.35pm.”

The Essex Police spokesman said the car towing the horse box trailer broke down before being involved in a collision with a white box van. Officers reported at the scene that the “horses have gone mad in the horse box”, the force spokesman said.

Highways England said initially that the collision involved a car towing a horse box trailer and a heavy goods vehicle.

Police closed a section of the A120 eastbound during the incident and warned drivers to avoid the area. A diversion route ran through Great Dunmow. Initially traffic was only being diverted around the junction via the sliproads.

The A120 eastbound between the B1256 (East) and B1256 (West) junctions reopened shortly after 9pm.

The air ambulance was also reportedly called, although this has not been confirmed. An ambulance service spokesman declined to provide any details when contacted.

Motorists said there was “standstill” traffic during the incident which would have impacted passengers on the way home to the region from Stansted Airport.