Police were called to the Grammar School for Girls at Wilmington over an email to the school that caused concerns.

According to a police spokesman they were called to the school just after 11am.

"Police officers attended and are carrying out standard search procedures," said the spokeswoman.

"Police have not evacuated the school as there does not appear to be a threat."

The school head teacher Maggie Bolton said: "We were just carrying out a test."

Parents have been told it was "a practice emergency evacuation in co-operation with local police."

According to text messages to parents from the school's attendance team they were testing systems which 'proved successful.'