A headteacher has apologised after a teenager was left alone in London following a school trip as the rest of the group headed back to Newcastle on the train.
The Discovery School has said there was "no excuse" for the serious error and that it will change its policies to make sure it does not happen again.
The pupil immediately alerted station staff at King's Cross and was put on the next service north, accompanied by train staff in First Class, and was met by a teacher in York.
According to reports, four teachers were accompanying the pupils on the field trip to the capital.
The Newcastle city centre school is for pupils aged 13-19 and specialises in science, technology, engineering and maths.