On 19 March, hundreds of British schools received emails threatening that they would be bombed unless money was paid. Although police said that the emails were not believed to represent any genuine threat, 400-or-so schools were closed as a result.
Two days later, following an investigation by the National Crime Agency (NCA), Hertfordshire police officers arrested a 19-year-old man in Watford on suspicion of blackmail and making malicious communications.
On 28 March, one week after the initial wave of threats, hundreds of British schools and colleges reported receiving more of the hoax emails.
Tonight the NCA and Hertfordshire Police have swooped again, arresting an 18-year-old man in the Abbots Langley area
Police believe the hoax bomb threats are linked. No more details are being offered by the authorities as the investigation is considered ongoing, however an earlier report at BBC News suggested the attacks might be linked to disgruntled users of a Minecraft server.