A passenger train travelled for 23 minutes at speeds of up to 80mph with a carriage door open, accident investigators have said.

During the incident, which took place in August on a Greater Anglia service, the train travelled for about 16 miles before the driver was alerted.

Greater Anglia said it had immediately conducted checks on all doors on similar trains of that type.

No one was injured in the incident, although passenger groups warned it could have had serious consequences on a more typically crowded train heading in the other direction.

The train was travelling out of London Liverpool Street to Southend Victoria in the early morning of 22 August when a passenger reported the open door to the driver at Hockley station in Essex at 7:20am.

The Rail Accident Investigation Branch (RAIB) has conducted a preliminary examination and said it will publish a “safety digest” in the coming weeks highlighting what lessons can be learned.

Greater Anglia’s commercial and customer service director, Martin Moran, said: “Safety is our highest priority. We immediately took the train out of service when this happened and carried out our own investigation into the incident.

“We have also carried out checks on every single door on that type of train that we have. No one was injured in this incident and there have been no further incidents since.”

Train doors, and who closes them, have been a core issue in continuing disputes between train operators and unions over the role of guards and driver-controlled trains.

The RAIB found that poor training and driver fatigue may have contributed to doors being left open on a London Underground train in a separate incident last September.

A Jubilee line service carrying about 30 passengers went between two stations with 10 doors open, travelling for 56 seconds at about 40mph, following a technical fault.