Originally Posted by dex
The editor of Jane's Fighting Ships was on NPR.
He said that the French are not part of NATO, so they did not have the info about the underwater positioning of the British sub.
It's always been messy. They've been participating in NATO exercises for years, but they have a reputation of attending all the planning conferences and then canceling at the last minute. That's bad enough, but then they show up at the post-exercise debrief.
Spouse had the same problem at one of her ASW commands where patrols were shared jointly among the U.S., Britain, & France. The U.S. P-3 would be on station waiting for the French to show up to relieve them... waiting... waiting... to be told that they'd just had a material failure and wouldn't be able to make it. Scramble another P-3 or a NIMROD. This could happen a few times a year with no hard feelings, but it seemed to happen more than 60% of their assigned missions.
The U.S. and Britain share info about SSBN patrols, although the OHIO class and the TRIDENT missile have made this less relevant than it was when the U.S. was patrolling in the North Atlantic and the Irish Sea in the 1980s. (OHIO class SSBNs don't even need to be out of homeport to be within range of most of their targets.) And any NATO nation will share info about their submarine movements so that other nation's boomers can quietly slink out of the way.
France is set to re-join NATO's command & control system in a few months, but it's still unclear whether they're going to share their SSBN area info.
There's some snarky speculation on military boards whether the French knew they'd hit a British sub, or if the Brits had to tell the French to check their sonar dome for British paint chips...