Britain will be okay, if they follow one of their greatest writer's visionary instincts: George Orwell made "Oceania" a part of the North & South American power construct in that novel for a reason. Putting aside the nightmare future he posited in the book, he saw instinctively that an England intimately interconnected with the United States was a bulwark against the Continental Fevers.
The spirit that animated Runnymede is certainly dimmed, but I don't think down-and-out for the count just yet--and may well be ripe for reanimation. Time will tell.