TWO reception-aged children escaped their school grounds without staff noticing and walked to their grandmother's house a mile away, The Northern Echo can reveal.

The boys, from Thirsk Community Primary School's reception class, which teaches ages four to five, scaled a two-metre metal fence at the far corner of school field at the end of lunchtime.

The pair then walked about a mile to their grandmother's house on the Norby Estate.

It is not known which route they took, but in order to reach the estate they would have had to navigate the busy A61 and the B1448 Northallerton Road by themselves.

North Yorkshire County Council launched an immediate investigation following the incident on Friday lunchtime and the school said in a statement that it takes pupil safety "very seriously".

Staff first became aware the boys were missing when they were not in line at the end of playtime and a spokesman said: "As classes lined up to go back into the school the two boys were not accounted for.

"An immediate search of the school and grounds was made and then the parents were called.

"The two boys were quickly located.

"They had arrived at their grandmother’s house about a mile away.

"They were collected from there by staff and parents.

"The school takes its responsibilities for pupil safety very seriously.

"Following an immediate investigation by the county council’s schools health and safety team, several measures have been implemented.

"Supervisory arrangements have been reviewed, all children have been spoken to about the importance of staying safe and reception class pupils are to play during lunchtime in their own enclosed area."

At its last Ofsted report in March this year, the school was judged to require improvement in all areas except in pupils' personal development, behaviour and welfare which was rated as good.