VH-Grumpy
I doubt they would just send up one intercept a/c. pilot refusal (of order) scenarios would be taken/have been into account in this situation. e.g. Maybe one or more of the pilots familly may reside, work in the area of possible crash site, coupled to the fact that no RAF a/c (in modern times) have shot down a UK reg civillian a/c killing fellow countrymen. Now, if the a/c was Russian/Chinese/Israeli that might prove more problems.
CIVOBS
There would be no chance of the pilot being in court, he would be covered by Crown Indemnity.
RS