Police have said the bomb threat emailed to a Norfolk school - which saw all its pupils sent home for the day - was a hoax.
King Edward VII Academy in King's Lynn was evacuated on Tuesday morning, after children had arrived for the day.
Police including dog units were sent to the scene, before leaving around lunchtime.
A spokesman for the police said: "There is no credible information at this time to say that this was anything other than a hoax."
Officers are appealing for information as they try to identify who sent the hoax.
The school, which stands on the Gaywood Road close to Lynn town centre, emailed parents at 9.15am.
A message from Emma Tilly, the school's head of safeguarding, said: "I am writing to inform you that we have taken the decision to send our pupils home today due to a suspected security risk that has come to our attention.
"We are currently working with the police who have confirmed it is a low-risk threat, however, we have a duty of care to our pupils, staff and parents and feel the best course of action is for everyone to be away from school while we investigate this further.
"Keeping everyone safe is our top priority.
"We will be continuing to investigate this with the police today and will provide a further update as soon as we have one."
Sarah Hartshorn, principal at the school which has 1,085 pupils, said: "As always, our top priority is the safety of our pupils, staff and parents, which is why, despite the police confirming the threat is low risk, we have taken their advice to send everyone home from school today.
"We are continuing to work with the police to investigate this further and will provide updates as and when we have them."
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