It's not RAF nor UK It's Nato ...
"The remaining question is what use then is the F35B in a deterrent role against the Russians. And the answer is little or none, just as the Su57 wouldn't deter us."
sorry to say it but aren't you still thinking as an independent island ...
the joint fighter is a NATO & Friends thing, no?
so if we count all F-35's in NATO & Friends then we can deter the Russians, Chinese or booth ...
i presume