The government has recently released classified files relating to UFO sightings, so if you have a few years to spare then you can go to the National Archives at Kew and have a good rummage.
Or I can save you the trouble :
Have you ever wondered why we have never found the missing link? Well, it’s because there isn’t one. Thousands of years ago, the great Galactic Empire needed to purge itself of its terrorists, dissidents and general malcontents. It sent out its starships to search the cosmos for a remote uninhabitted planet to act as a sort of interstellar Australia. It found us – or rather not us, as there was nobody here.
They did a big roundup and dumped all the crud down here on planet Earth, leaving our ancestors to fend for themselves. UFOs are simply Galactic Prison Service ships making sure that we don’t get off the rock. Apollo 13 was a warning shot. The USA knows this which is why it is trying to take over the world in the hope of negotiating a release.
And if you think this is all bollocks, ask yourself why the human race is such a crock of shite…