Rural area, near RAF Great Rissington, Gloucestershire, U.K.
I was an avid plane spotter, was watching out for planes, with binoculars.
This was an area frequented by test planes and many U.S.A.F. bombers.
I think I saw the U2 at extreme altitude before it got any publicity.
That day, one circular saucer rose above hilly wooded horizon, about 2 miles away, edge on, travelling not very fast in a horizontal plane.
Then banked away, clearly spinning, about 50-60 rpm, I'd guess.
Rose a little above the horizon, then fell away below horizon.
To be followed by 8 more in line astern.
I had the binoculars on it/them in turn, and I can't remember if there were 2 visible at any one time, but the timing and motion was such that it would be highly unlikely if it were one repeating the manoeuvre another 8 times.
Color was aluminium grey, diameter of about 30', I'd guess, at that distance it was difficult to tell.
I didn't get a long look edge on but I think I glimpsed a bulge at the center.
Have spoken about this for years and, of course, everyone dismisses it.
Got my Dad to report it to R.A.F., but, you know the rest.