Parents across Italy left work in a hurry on Wednesday morning after an emailed bomb threat landed in the inboxes of around 6,300 schools. Education minister Giuseppe Valditara said 312 buildings were cleared, from Rome and Milan to Naples, Palermo and Bologna. Bomb disposal teams and postal police checked the sites and found nothing.

The message itself was violent and rambling. Its author claimed to be “Mikhail Andropov”, supposedly the head of a misogynist extremist outfit, a name already attached to fake threats against European airlines and broadcasters last week. It also targeted Prime Minister Giorgia Meloni, who said there was no “concrete danger” and that the aim was to spread alarm. A cabinet-level meeting on the threats was scheduled for the afternoon.

At the Mamiani high school in Rome, some pupils first mistook the alarm for the bell signalling break time. Defence minister Guido Crosetto summed up the frustration: sending such an email to a school or an airline, he said, is “too easy”.

The wave did not stop at the Alps. Schools by the hundred in Scotland, in Northern Ireland and across the Irish border got comparable emails, but police there judged them hoaxes and advised against evacuating. Officers in Northern Ireland said the emails appeared to come from outside the UK, and Irish police spoke of a “generic communication”.

For Italian schools it was the third such episode in a month, following threats on October 19 and November 2. Officially, nobody has yet been named as the culprit. Still, the timing feeds wider unease in Europe about hybrid tactics, after recent hacks of supermarket refrigeration, drone incursions and false alerts that hit more than 20 commercial flights.