As The Telegraph and many other British newspapers are reporting, the National Health Service (NHS) has had its email communications turned to porridge today.
Not by malicious hackers sponsored by a foreign state, but instead by a simple human error that saw a test email sent to some 1.2 million NHS employees.
And, as I explain in the video above, whenever a recipient replied to the message (for instance, "Did you mean to send me this email?") their response was sent to the other 1,199,999 people on the list.
Oh dear oh dear.
What happens next? Well, typically other people get angry at the "stupidity" of the people who replied to the email, so they also reply to the mailing list asking that no-one else reply to the mailing list...
You've got yourself an email storm.
Which wouldn't be a life-and-death situation if umm.. it wasn't the National Health Service which was suffering from email paralysis.
Hopefully things are returning to order by now.