Just to throw a spanner in from a very different angle....and this is very relevant to the RAF.....
Apart from the nuclear submarine fleet, all other capabilities across the 3 Services require us to burn oil in one form or another.
Given the RAF uses over 60% of all fuel burned in the MoD (the largest carbon emitter of any govt dept) and carbon limits will be applied as part of UK law (already passed), coupled with the increased cost and scarcity of fuel, can you see us being able to fly those jets to meet any task?
Real world stuff we will see in most of our Service careers - not tree-hugging pish either - real operational limits.