Of the many and varied kinds of UFO encounters that have been reported since 1947 – the year in which the Flying Saucer was “born” – some stand out more than others. One category of encounter that particularly intrigues me involves UFOs caught on radar. And when the incidents involve pilots pursuing UFOs through the sky – while ground-radar is tracking them at the same time – this makes a fairly persuasive case for the reality of a genuine UFO. It gets weirder, though: what about incidents in which UFOs are tracked on radar – sometimes by staff at more than one military base – but the UFOs cannot be seen visually. Its almost as if some UFOs have the ability to become invisible to the human eye. Maybe they do. That’s the theme of today’s article. I’ll share with you three fascinating cases. The first comes from the late J.R. Oliver, whose wife very generously gave me permission to use the account of her late husband, and which makes for fascinating reading. Oliver prepared the account some time before his death, of which the following is just an extract from a much longer account:

“In August 1949, in order to test the updated air defenses of England against attack, Operation Bulldog was launched. Operation Bulldog’s attacking forces consisted of aircraft of the Benelux countries supported by U.S. air squadrons based on the continent. Flying from various airfields in Holland, France, Belgium and Germany, their objective was to attack London and other prime targets in southern and midland England, without being officially ‘downed’ by fighter aircraft brought into action by the defensive network of Fighter Command. The radar defense chain extended from Land’s End, along the south coast and up to the north of Scotland, overlapping at all heights from sea level to about 100,000 feet. Even so long ago, it was almost impossible to fly a glider across the Channel without it being plotted. The exercise ran for fifteen days and was structured in such a way that the technical resources and personnel of the defensive screen were stretched to the limit.”

It wasn’t long at all before something very weird occurred, as Oliver noted in his letter: “Within about fifteen minutes, the PBX operator came in, approached the Duty Controller and advised him that Bethe first to see the contact and my plot was the first to go on the plot board. As other operators took their positions, more plots were called out concerning position of the object and its height. The object was flying roughly parallel with the south coast, from west to east. Reaching a point out to see off the ‘heel’ of Kent, it abruptly turned north and as it approached the Thames estuary we passed it on to Martlesham radar, with whom we had been in contact via the PBX link, and whose radar area impinged on our own. Shortly after, we lost contact with it, due to the limit of our own radar range.”

Oliver then noted something even more incredible: “It was a simple matter to assess the speed of the object from the times and distances between plots and its height was directly read from our Type 13 radar, designed to read the height of any aircraft within its range. Flying at close to 50,000 feet, the air speed of the object we had observed and plotted in accordance with RAF standard procedures was assessed at very nearly 3,000 miles per hour [italics mine]. The general consensus regarding its size, among the very experienced radar personnel engaged in the operations, was that the object offered an echo similar to that of a large passenger or freighter surface vessel, something in the region of 15,000 or 20,00 tons [italics mine]. Word filtered down that on approaching Bempton radar in Yorkshire, the object suddenly increased speed and headed directly upwards, vanished off-screen at about 100,000 feet.”

Despite the careful tracking of the huge object – by the radar operators of several military bases – the UFO was never visibly seen: it was only encountered on the radar screens. Now, let’s take a look at another case that involved an “invisible UFO.” It comes from a man named William Maguire. In September 1952, he was serving in the U.K.’s Royal Air Force – on radar. Of his experience of the UFO type – that occurred at a military facility called RAF Sandwich in the south of England – Maguire told me: “The mechanics were being blamed for not calibrating the instruments properly; we were being blamed for not interpreting the readings properly. But the obvious answer staring us in the face, on every single instrument on the base, was the fact that there was sitting up at an unbelievable height, this enormous thing with the equivalent mass of a warship and it just stood there…and stood there…and stood there.”

So, we have a second case that involves the tracking by radar of a gigantic craft, but that is not encountered visually. On March 26, 1957, there was yet another amazing encounter. The document states in part: “A report was received from Royal Air Force Church Lawford on 26th March, 1957 of a sighting of an unusual nature. The object moved at a speed timed at exceeding 1400mph. This in itself was unusual as the object had accelerated to this speed from a stationary position. No explanation has yet been found for this sighting but a supplementary report, including a copy of the radar plot, was requested and has been received from Church Lawford this afternoon.”

It’s important to note that the “sighting” was seen on radar. Yet again, nothing was actually seen in the sky. Invisible UFOs? Maybe. There is, however, another explanation – very different, but also very intriguing – that I’ll get to in part-2 of this article.