Passengers were dragged along Tube station platforms after their coats were trapped in train doors.

These "trap and drag" accidents happened at Archway on February 18 and at Chalk Farm on April 20.

According to the Rail Accident Investigation Branch (RAIB), which released its report into the accidents today (June 27), this happened because the doors' control systems did not detect the trapped coats.

In the first incident, which happened around 3.50pm on February 18, the passenger was getting off a Northern line train at Archway station when their coat got stuck in the closing doors.

The passenger was dragged for around two metres along the platform before they fell to the ground, and their coat became free.

A second person who was holding onto the passenger also fell to the ground.

The train moved about 20 metres before the driver applied the brakes, resulting in serious injuries to the passenger.

The RAIB found that even though the driver was aware of the passenger and their companion, he did not know that the coat was trapped until the train had already started moving.

The pilot light that indicates if the train doors are safely shut can still illuminate even when something is caught between them - something which the train operator was not aware of.

In the second incident, which happened at 11.03pm on April 20, a passenger was trying to board a Northern line train at Chalk Farm station.

When the doors began to close, they moved back but their coat was caught in the doors.

The train moved about 20 metres, dragging the person along until they were freed of the doors.

This time, the driver was unaware of the whole occurrence and went on with the journey.

The passenger sustained minor injuries to their left elbow and both knees, as well as psychological distress.

RAIB has made several recommendations for the London Underground and provided three learning points to prevent such accidents in the future.

The RAIB said: "The recommendations concern the understanding of risk arising from trap and drag events, the risk mitigation options, the minimum station dwell times and how the design of the task and the cab environment can influence train operators’ attention and awareness."

The learning points from the RAIB highlighted the importance of "documenting action plans" for these incidents, "promptly reporting notifiable accidents", and ensuring train operators understand the risks of relying on the pilot light when deciding whether it is safe to start the train.