Mr Blair has said: “This is incredibly concerning news and my full support goes to the school staff and pupils who are currently dealing with this.

“Those responsible for this sinister threat must be condemned in the strongest possible terms. No child should be put in this situation and no parent should have to worry about the safety of their child when they send them to school.

“I would like to reassure parents that the PSNI are currently investigating the incident, and they have increased patrols in the areas affected.

“It is vital that anyone with information contacts the police immediately to help them with their investigations.”