18th December 1979
Telex, phones and telegram cables go quiet
As a result, the islands had no direct phone, fax, telex or telegraph connections to the mainland. Fortunately, they did have one remaining connection to France in place, so emergency messages could still be sent.
The connections to the mainland were down for three and a half days all told, during and after which the States Telecommunications Board considered what could be done to improve the resilience of the link.
It wasn’t the first time Guernsey’s connection with mainland Britain had been severed. It happened as far back as 1877 when it took more than a month to repair the damage.
A problem with a history
It happened twice in 2016: once in January and again in November. The latter of those was caused by a ship dragging its anchor through the undersea cables, snapping all three. On that occasion, BT, Sure and JT warned it could take three weeks to repair and, again, all internet and voice communications had to be routed via France. Fortunately the “three week” repair was actually completed in seven days.
Guernsey, Jersey and the other islands are today connected by several cables so it is unlikely that they would ever be cut off entirely from the outside world by accident. In some places the cables are buried, but not along their full length. Unfortunately, even where they are under the sea bed, if a ship should drag its anchor across them there is still a chance they would be damaged. For this reason, the path of each cable is marked on maritime maps and there are restrictions on dropping anchor or fishing in their vicinity.