Legality: Mapping the Military for Civil Acountability

Most countries have laws banning actions that endanger national security; sometimes these laws are worded such that there needs to be an intent to endanger national security for the action to be illegal, and sometimes the laws are worded in a way to make even the accidental endangerment of national security punishable. Even in a country generally considered to be "non-authoritarian" or "democratic", if the state prosecutor really hates your guts they might be able to construe your mapping of details in a military area as sabotaging national security, something that might not hold water in the courts but cost you time, money, and nerves to defend against.

I'd say it is safest to map the military installations of other countries but then again some "non-authoritarian" and "democratic" countries do not shy away from kidnapping foreign nationals on foreign soil if they perceive them a thread to national security.

You'll have to weigh the risks for yourself; we cannot tell you what you "can" or "cannot" do. From OSM's point of view we're certainly happy to receive and host your contribution if it doesn't violate the laws of the United Kingdom and is in line with our own practices.