A young boy was found wandering alone in the street after going missing from school this morning.
An urgent investigation is underway at Devonshire Primary Academy in Layton after the youngster was found outside and taken to a nearby children's centre.
The pupil, who cannot talk due to his special educational needs, was later collected by staff and taken home by his parents.
It is understood he managed to get out through an unlocked door at the school, which is expected to inform parents in a letter due to be sent home when classes end this afternoon.
Nick Toyne, headteacher of Devonshire Primary Academy, said: “Unfortunately, due to a lapse in our classroom routines, a door was left open and a pupil was able to leave the premises.
The child was found a short while later and returned to school safely and unharmed.
“As a school we take the safeguarding of all our pupils extremely seriously and I am mortified that this has happened.
“A full investigation is taking place and procedures have already been reviewed and changed to ensure that this mistake will not happen again.
“We are also liaising with the safeguarding team at the council.”