Military Risk
Nigel,
I do not know what JSP553 says. The old JSP 318B had a section on operating in "Hostilities and situations of Direct Threat" which empowered the Operations Branch to approve flying to the provisions of SDs and OEC releases, for both operational and work-up training flying "but the risks involved as a result of the limited [MOD(PE) as then was] trials carried out for the OEC release and the probable lack of trials for SDs must be borne in mind in approving the amount of such work up."
A further section where the "operational need is overriding" introduced the concept of Operational Necessity Service Deviations (ONSDs) normally requiring approval at 2* or above. ONSDs were to be approved "sparingly, and only when life is at stake (my bold), because the lack of trials results available to the approving authority will make a realistic risk assessment difficult."
Whether these are still the current "rules" I would not know - but bear in mind none of these procedures authorise you to take the further risks of flying an aircraft which is not airworthy - they are there to allow things like UOR equipment to be introduced, flights at higher AUWs, changes to flight limitations, new weapons to be introduced, etc, etc. Unless JSP 553 is different there is as far as I can see no change in the definitions that allows lower airworthiness standards to be applied to operational flying - but maybe a contributor to this thread knows differently!
JB