The emergency alert test unleashed disruption today as runners at this afternoon's London Marathon were left staring at their phones in bewilderment and a BBC newsreader was interrupted live on air.
Footage from the finish line showed exhausted long distance runners who had just completed the arduous 26-mile route picking up their phones to get in touch with their loved ones when the loud noise abruptly sounded.
All people with 3G and 4G-capable mobile phones in the UK were supposed to receive a loud 10-second notification at 3pm on Sunday afternoon as part of a government test of a new emergency alert system - though customers on some networks reported receiving no notification at all.
