It was inevitable that this would happen one day despite being a million to one shot.
These subs these days are necessarily quiet and in fact I understand that the only way to detect a Trafalgar sub moving at low speed is by looking for an absence of noise, what you might call a black hole in the sea. Not an easy task.
I also understand that American and British navies exchange information on patrolling routes for their subs to eliminate this problem while the Russian subs remain noisy enough to be detected. That just leave the French boomers as a possible problem. It has been suggested that the british and French navies should exchange patrol route information as well but I have always said we need the boomers because of the French and not the Russians so that would destroy the effectiveness of our deterant