The parents of a three-year-old boy who was left strapped into the seat of a school bus for four hours yesterday morning, have started legal proceedings against the TGO transport company responsible.

Maria Luisa Brazo said goodbye to Pablo at 8.45am when he was picked up by the school bus for the short journey to the Font de la Orpina junior school on the Can Serra residential estate in Vacarisses (Barcelona).

He was strapped into his seat, as usual, by a female teaching assistant responsible for supervising the children.

However, she forgot to drop him off at his school, and he was left on board as the driver continued on to a second school before leaving the vehicle at the Olesa de Montserrat depot at the end of his shift.

Pablo was not found until around 1am by one of the afternoon shift drivers, who gave the terrified infant, who had wet himself, something to eat and drink before dropping him off at his school.

His mother was finally informed about the situation shortly after 2.30pm.