Back in the late 70s my then boyfriend and I were out for a drive near what was then Enfield, Middlesex (now classified as north London). We were heading back from Waltham Cross, driving down a windy, hilly road, alone on the road, when half of a very large, round craft appeared above us (the other half was obscured by the hill), hovered for a few seconds, then simply disappeared. We both looked at it, then each other and simultaneously said, 'Did you see that?'
No idea to this day what it was but we both believe we saw a UFO.