They liked us. In fact, they liked us so much that they would sometimes invite people on to their ships, take them for rides around the universe, tell them all about their alien technology and culture, then insert large probes into their bottoms for reasons that are probably none of our business. These guests were not selected at random and typically had several crucial features in common: they were always from the country; they had very few friends; they were never in possession of any sort of camera; and they never remembered anything until they were either under deep hypnosis or on television, preferably both.

But it has been a very long time since we've had a decent UFO sighting. Indeed, it's been so long that many people have forgotten what UFOs look like. This has had a deleterious effect on UFO sighting statistics, which have fallen with alarming alarmingness over the past few decades. It's no doubt happened that people have seen large, perfectly smooth metallic saucers hovering in their back paddock, surgically removing the stomach lining from cattle, and not realised that it was, in fact, a bona fide UFO and not a reminder to finally say no to cold pizza just before bed. The reasons for the drop-off in UFO sightings are many and complex. Extensive studies by the Institute for Making Up Statistical Trends have established a distinct inverse correlation between alien visitation and the development of human photographic technology.

That is, the better we got at taking sharp, high-resolution pictures of things, the fewer aliens spaceships we saw. Support for this is a matter of record. Back in prehistoric times when all people could do was paint pictures into cave walls and chisel images into stone slabs, the Earth was positively teeming with aliens.

They helped us build pyramids and temples, and also formed some of civilisation's earliest executive management teams, with much of their unintelligible language still very much in evidence today. Once cameras were invented, however, the aliens seemed less willing to show themselves. As cameras became cheaper and more plentiful, the aliens seemed even more reluctant to drop in, and now that digital cameras are about as common as teenagers with severe eardrum damage, visits from our alien friends appear to have dropped off altogether, if not totally. The key question we now face at this point in our ongoing investigation into alien culture is: what does this teach us about the aliens?

Here are several important notes: (1) Despite their advanced intelligence, the aliens are extraordinarily shy and self-conscious about their appearance. This supports the long-held theory that their visits to Earth are on the urging from a more self-confident and attractive alien civilisation who just want them to get out and meet people, otherwise they're going to end up as the unmarried alien civilisation who lives all alone on the corner in the large house with all the cats.

(2) That human civilisation was a science project by some alien students whose report has been assessed with a passing mark, so there's no need for them to return. (3) That the last person the aliens abducted had just been to an all-you-can-eat Mexican restaurant, and there's no way they're going to travel 50 billion light years to put themselves through that again. (4) It's just God messing with our heads again. Infinitely more disturbing is a fifth theory. This holds how the aliens have not stopped visiting us at all. The Government may want us to think they have, but it's far more likely that the aliens walk among us posing as normal Earthlings, trying hard to understand our culture, our society and why we keep buying gym memberships when we almost never go.

What is their plan? Do they come in peace? And should they bring a plate? Will they want to take over our beloved planet, or just rent? All we can do is wait, watch and make absolutely sure that should one of their gleaming spaceships appear before us, to take a nice, sharp photo of it with our phone before passing out.