I would have thought he might have asked for some details as to how much poo might result if it didn't work out! Answer - a lot and it didn't!
SIS would have planned the operation, but would have made a "submission" to the FS for his authorisation. The submission details in a one or two page letter the intelligence to be gained, a brief outline of the plan, and a risk assessment. SIS don't make submissions unless they are fairly sure the FS will authorise it - so the "intelligence to be gained" argument has to substantially outweigh the risk.
The FS usually just signs off the submission - he would never get involved in requesting further detail.