Passengers were thrown from their seats and hit by falling luggage on a train being driven at 50mph (80km/h) above the speed limit, investigators said.

The Lumo service passed over three sets of points near Peterborough at 75mph (121km/h) at 10:20 BST on 17 April, the Rail Accident Investigation Branch (RAIB) said.

The maximum permitted speed limit at those sections was 25mph (40km/h).

A full investigation is being carried out into what happened.

At the time of the incident, British Transport Police said 15 passengers reported minor injuries and were offered medical assistance by paramedics.

The force received a report that the train's emergency brake was applied.

In a preliminary statement, the RAIB said: "Passing over the points at this speed (75mph) meant that the train suddenly lurched sideways.

"The sudden movement of the train resulted in some passengers being thrown from their seats and in luggage falling from the overhead storage in the passenger compartments.

"This resulted in a number of minor injuries being sustained by passengers."

The service involved was the 08:20 departure from Newcastle to London King's Cross.

It came to a stop after passing through Peterborough, where it had not been due to call.

The RAIB said its full investigation would include look at the way the train was driven, any factors that may have influenced the driver, the condition of the signalling system, the nature of the injuries, and any underlying management issues.

Lumo said the safety of its customers and staff was it "highest priority" and it would be "cooperating fully" with the RAIB's investigation.

It said it would not comment further until the investigation had concluded.

Lumo, owned by FirstGroup, began running services on the East Coast Main Line between London King's Cross and Edinburgh Waverley in October 2021, competing against state-run London North Eastern Railway.

It is an open access operator, meaning it does not receive government funding.