"An operational matter"

When the GCSB refused to reveal whether it was being bribed by the NSA, it hid behind a clause in the Intelligence and Security Committee Act that the ISC could not inquire into "any matter that is operationally sensitive, including any matter that relates to intelligence collection and production methods or sources of information". So what's "operationally sensitive" according to the GCSB? Looking at the questions and answers received, there's an interesting pattern: Whether the GCSB spies on all our metadata is not "operationally sensitive". Neither is whether it spies on the citizens of other Five Eyes partners - things you'd expect to go to the core of their operations. But when Parliament asks about whether it is obeying the Public Finance Act, or whether it has formal NSA moles in its organisation, then suddenly its an "operational matter" which they can't answer. The natural conclusion: they do and there are - because if either allegation was false, they'd just deny it.