September 19, 1952 — nr. RAF Topcliffe, North Yorkshire, England
10:53 a.m. During Exercise Mainbrace maneuvers, a silvery, spherical UFO appears near RAF Topcliffe in North Yorkshire, England, following an RAF Meteor jet (possibly piloted by Flight Lt. John W. Kilburn and Flight Lt. Marian Cybulski) about to land.
It has been following about 5 miles behind the jet at 15,000 feet, swinging like a “falling sycamore leaf” and descending. As the jet turns toward Dishforth, the object follows but begins rotating on its axis then suddenly accelerates and disappears. Several ground crew members of RAF 269 Squadron (Master Signaller Albert Thomson, Sgt. Flight Engineer Thomas Deweys, Flight Lt. R. Paris, and Leading Aircraftman George Grime) and civilians also see it. Prince Philip suggests to RAF Air Marshal Peter Horsley, who is serving as equerry to the duke, that he investigate credible reports of UFOs, especially those by fighter pilots who have seen them. He arranges for RAF Fighter Command to send copies of any reports for examination at Buckingham Palace and begins an informal study that lasts until 1955. [Eberhart]
Sources:
UFO Flying Saucers (Gold Key) comic;
“Check for ‘Saucers’ At Naval Maneuver,” El Paso (Tex.) Herald-Post, September 20, 1952, p. 16;
Edward Ruppelt, The Report on Unidentified Flying Objects, pp. 195–196;
Richard Hall, The UFO Evidence, pp. 162-163;
Richard Hall, “Military Secrecy: Sailors, Soldiers, and Airmen,” MUFON UFO Journal, no. 153 (November 1980): 4–5;
Timothy Good, Above Top Secret, pp. 31–32, 450;
Kevin Randle, Project Moon Dust, 1998, pp. 61-63;
David Clarke, The UFO Files : The Inside Story of Real-Life Sightings, 2nd Ed., pp. 47-48;
David Clarke, “The Prince and the Saucers,” Fortean Times 406 (June 2021): 18–19;
David Clarke, “Phantoms of the Sky,” Fortean Times 445 (June 2024): 28, 35;
Brad Sparks, Blue Books Unknowns Catalogue, Case 830-831, p. 173;
Jerome Clark, The UFO Encyclopedia, 3rd Ed., p. 376;
Jerome Clark, The UFO Encyclopedia, 4th Ed., p. 420;
British MOD 1998 DEFE-24-2001-1 file;
NICAP, “Swaying Silver Object Follows Jet”;
Richard Hall, “Operation Mainbrace Sightings”;
David Clarke @shuclarke , “Operation Mainbrace UFOs”
Nick Redfern, “UFOs and NATO: The Mainbrace Affair,” Mysterious Universe, April 22, 2014;