Senior teachers at Montgomery High School have been praised for opening as normal.
There were calls for the school, in Bispham, to remain closed following threats to leave a trail of 'bullets, bodies, and blood' there this morning, with some parents deciding to stay clear until an arrest has been made.
But as police officers guarded every entrance in a bid to reassure parents and pupils, neighbourhood police inspector James Martin said opening as normal was 'important'.
He said: "The school has opened, which I think is very important, and that helped us to get everything back to normal for the spring term."
Insp Martin said he was unable to say how police had judged the threat to be a hoax because the 'investigation is being conducted by another department'.
He added: "Every threat is processed by police and it's worked on by the information and the intelligence we have.
"People are trained to make decisions on whether the threat is credible or not and at the moment we're not treating this as credible."
Students who defied the threats, which were first posted around 10 days ago, were ushered inside the school by staff - some of whom were drafted in from Aspire Academy - as TV crews filmed outside.