Police say they are working closely with the school following the incident on Monday 10th December.
Officers were called into St Michael's C of E in Heavitree on Monday.
The knife was not taken out of the child's bag until it was confiscated by staff at just after 9am.
Mixed picture as DCC overspend reversed but savings target off
Devon County Council is predicting it will miss its £50m savings target
Seven fire crews tackling blaze at North Devon derelict house
Broke out near Bideford
Devon man raises thousands for Hospiscare
Jim Bray received a 'Hospice Hero' medal
Teenage boy arrested following Plymouth nightclub fire
13-year-old released under investigation
Neighbourhood plan to go to referendum
Councillor praised for "dogged determination"
Paignton ‘eyesore’ demolition plan splits town
'Are we really prepared to see yet another hole torn into the heart of Paignton?'
