“Documents from the Ministry of Defense recently declassified archives show staff believed aliens could visit for “military reconnaissance”, “scientific research” or “tourism”. Just a small tidbit here. One thing about me is that I once worked on the Defense Flying Complaints Investigation Team, which was manned mostly by RAF Police investigators. The Team’s primary role was to investigate alleged breaches of the low flying regulations by military aircrew.
Occasionally, however, we were tasked by the MOD with conducting field investigations into the more intriguing ‘UFO sightings’. There was nothing cloak and dagger about these investigations, which consisted of witness interviews and establishing whether the sighting had a straightforward explanation or not. This included examining radar replays of UK airspace from the National Air Traffic Service.
On conclusion of the investigation, we would compile a report for the MOD who would in turn write to the person who reported the sighting, with the result of the investigation.
I can only speak for my own experience during the time I was on the Team, but the reporting of the files released by the National Archives seems consistent with what we found.