A grandmother watched helplessly as a train pulled away from the platform with her grandchildren on board.

Jean Butterfield had ushered Jordan Williamson, seven, and his sister Ashleigh, three, on to the train.

But, before it pulled away, she realised she had left a bag on the platform and stepped out to get it.

She was left horrified as she turned back with the bag to see the doors closed behind her and the panic-stricken faces of the children peering out at her.

She asked a nearby staff member of the Tyneside Metro service to help after the incident at Newcastle Central Station.

Mrs Butterfield said: "I was pressing the button frantically for the doors to open, but the train went off. Ashleigh was hysterical and shouting please go back for nana.

"I found someone and asked them to radio ahead and tell them what happened and they said if I got the next train the kids would be on the platform waiting.

"Sure enough they were there, but there was no one from the train company with them. Instead, it was a lady who had been on the train."

A spokesman for Nexus, which operates the Metro system, said: "We aim to ensure passengers have as smooth and uneventful a trip as possible.

"In this case things didn't quite go according to plan and we are carrying out an inquiry to find out what happened."