In 1956 personnel from the Royal Air Force and the United States Air Force had a series of radar and visual contacts with UFOs over airbases in England. The incident was classified for 13 years and still remains unexplained.
At 9:30pm on August 13, 1956, a radar station at Bentwaters, Suffolk, England, where the Royal Air Force and the US Air Force jointly ran an air base, picked up a target 25 to 30 miles to the east-southeast. The return was in all ways but one like that of an ordinary aircraft; what made it remarkable was that it moved in a straight line from its original location to a location 15 or 20 miles northwest of Bentwaters.
A few minutes later a group of about a dozen targets were spotted eight miles southwest of Bentwaters. The Bentwaters radar operator later told Project Blue Book investigators that "these objects appeared as normal targets on the GCA (Ground Controlled Approach) scope and normal checks made to determine possible malfunctions of the GCA radar failed to indicate anything was technically wrong." In front of the 12 or so objects, radar indicated, three others flew in a triangular formation, all separated by 1000 feet. The objects in the rear were scattered at irregular intervals, and in all they covered an area of six or seven miles.
They seemed to be moving at 100 mph, more or less, and were heading northeast. Forty miles from Bentwaters something bizarre occurred: all the targets appeared to converge into one huge target, which caused a return several times bigger than a B-36 would under comparable circumstances. After remaining stationary for the next 10 or 15 minutes, the target resumed movement to the northeast, then stopped again for three to five minutes. Finally, it was lost to radar heading north. All this occurred over a 25-minute period.
A T-33 on its way back to Bentwaters was directed to look for the objects, but a 45-minute search, unaided by airborne radar, resulted only in sightings of a bright star in the east and a coastal beacon. The pilots' inability to see the objects caused this aspect to be the most controversial - critics would say weakest - part of the sighting, though atmospheric physicist James E McDonald, who conducted an extensive analysis of the case, argued that for a number of technical reasons the returns could not have been caused by anomalous propagation. At 10pm, only minutes after the above episode had concluded, another target, again as solid as an aircraft, appeared on the screen. It moved at more than 4000mph the operator thought - though McDonald concluded the real figure should have been 12,000mph - to the west until it got within 25 miles of the station when it vanished from the screen.
At 10:55 yet another target was picked up, this one 30 miles to the east, heading west at 2000 to 4000mph. It passed nearly directly overhead and disappeared from the screen 30 miles from the base. This time observers both on the ground and in the air (a C-47 pilot glimpsed it beneath his plane) saw the object.
Now the center of action shifted to nearby Lakenheath AFB, to the west-northwest of Bentwaters. During or immediately after the radar/visual sighting, Bentwaters notified Lakenheath, where ground personnel saw a luminous object come in on a southwesterly heading, stop, then shoot off toward the east. Two white lights appeared (apparently from different directions; Blue Book records are vague on this point), "joined up with one another, and both disappeared in formation together." Before doing so, the UFOs performed "rapid acceleration and abrupt stops," recorded on two radar screens at Lakenheath.
At midnight Lakenheath called the chief fighter controller on duty at the RAF Station at Neatishead, Norfolk, and reported that a strange object was buzzing the base. The fighter controller, F H C Wimbledon, recalled:
"I scrambled a Venom night fighter from the Battle Flight through Sector, and my controller in the Interception Cabin took over control of it. The Interception Control team would consist of one Fighter Controller (an Officer), a Corporal, a tracker, and a height reader. That is, four highly trained personnel in addition to myself could now clearly see the object on our radarscopes."
The Venom headed in its direction, saw a brilliant white light and picked it up on its radar, but soon both the light and target disappeared. Immediately afterwards, the interceptor was directed to another target over Bedford, north of Cambridge, and the navigator locked on to it on his radar; it was, he said, the "clearest target I have ever seen on radar."
This object, 10 miles east of Lakenheath, suddenly appeared behind the plane, but when the pilot turned around, the UFO remained on his tail. According to a statement by one of the ground radar operators:
"The pilot tried everything - he climbed, dived, circled, etc, but the UFO acted like it was glued right behind him, always the same distance, very close, but we always had two distinct targets."
After 10 minutes, with fuel running low, the Venom headed back to the base. The UFO followed it a short distance, then stopped and hovered in the sky. A second Venom was scrambled, but equipment problems forced it to abort its mission. Two ground radars tracked the UFO's departure northward at 600mph. Lakenheath continued to note periodic anomalous radar echoes until 3:30am.
This extraordinary episode was classified until 1969, when it was discussed in the final report of the University of Colorado UFO project (informally known as the Condon Committee, after its director, physicist Edward U Condon). The account characterizes the Lakenheath/Bentwaters case as the "most puzzling and unusual in the radar-visual files. The apparently rational, intelligent behavior of the UFO suggests a mechanical device of unknown origin as the most probable explanation of this sighting." Later and elsewhere, the committee's investigator, physicist Gordon David Thayer, would write:
"There is simply no way that any known sort of anomalous propagation effect could account for this. In fact, any explanation even remotely conceivable seems to demand the presence of some physical object in the air over Lakenheath."
In a 1974 book, debunker Philip J Klass argued that a combination of operator error, anomalous propagation, and meteors had caused the radar contacts and visual sightings. he debated the issue in letters with Thayer, who countered that Klass's interpretation was based on factual errors, implausible assumptions, and technical misunderstandings. Martin Lawrence Shough, who conducted an in-depth reanalysis of the case in the 1980s, judged the Lakenheath/Bentwaters events to be "probably the most impressive of their kind on record."