A case in point, Localiser Green.....
Remember reading about the following incident (which I think happened sometime last Year).
Gemini DC10F, out of EINN into (if memory serves correct) suffers (uncontained?) Eng failure somewhere over Western UK, resulting in some structural damage and fire warnings.
Crew declare emergency and ask for EGLL. LATCC offers EGVN (Brize - which is by now closest suitable that's open - it's late evening) - crew ask again for EGLL and are vectored over a heavily populated area in a potentially damaged aircraft for a landing on the 27's.
As you say, it's the Commanders decision....