Horizon took a funny turn this week. The new series started off gently enough – there was a nostalgic look back at 60 years of science on the box, then an exploration as to what makes us clever (the fun this entailed when vaguely well-known people sweated through a series of IQ tests). But last night it wanted us to get to grips with something very slippery indeed, so slippery that even the eminent scientists responsible for unleashing some of the more frontier theories in particle physics readily admitted their conceptual limitations in understanding their own formulations.

With such weighty gastronauts as Heston Blumenthal, Jamie Oliver and Hugh Fearnley-Whittingstall all aboard Channel 4's Big Fish Fight jamboree, Gordon Ramsay obviously couldn't bear to be left standing on the quay. In fact, with Gordon Ramsay: Shark Bait he has made the most provocative film of the season, a punchy documentary in which the shouty superchef did some bold poking about in the hideous innards of the global trade in shark fins.

The classical-music industry loves dead icons; witness the endless reissuing and remarketing of recordings by Kathleen Ferrier and Jacqueline du Pré. Canadian pianist Glenn Gould died from a stroke at the age of 50 in 1982 and his seminal Bach discs have never been out of the catalogue since. Françis Giraud told Gould’s story on screen before in his 1993 film Thirty Two Short Films About Glenn Gould, an imaginative series of vignettes depicting scenes from Gould’s life.

There was always going to come a time when Little Britain had to stop. For a couple of years the heavily milked franchise seemed to be on a tape loop on BBC Three. Its international expansion - to the Greek islands one Christmas, to America for an entire series – suggested that its stars were getting itchy feet. That hankering to grow wings has manifested itself in the form of Come Fly With Me, a spoof docusoap in which Matt Lucas and David Walliams present an entirely new set of grotesques. In last night’s third episode, the gallery was still growing.

In 1994 half a million Rwandan Tutsis were slaughtered over a period of six weeks. Among them were the four brothers and two sisters of Jean-Pierre Sagahutu. His mother was raped before she too was killed. His father, a doctor, was intercepted on the way to the hospital and, when he was unable to pay a fine at a roadblock, was pulled from his car, hit over the head with a blunt hoe and taken to a ditch where his body was dumped. Rwanda, to which three million refugees have returned as the economy has tripled, is known as the great success story of Africa.

Ever since Catfish appeared in the States earlier in the year, debate has been raging about its bona fides. On the face of it an ingenious documentary playing smartly with the potential and pitfalls of social networking and the nature of personal identity in the cyber age, the film has triggered cries of “foul” from a number of critics and viewers. Morgan Spurlock, who made the junk-food odyssey Super Size Me, has called Catfish “the best fake documentary I’ve ever seen”.

Once upon a time, just before Lord Reith began permanent rotation in his place of rest, there was a hideous botchjob of a television genre known as the docusoap. It wasn’t quite documentary and it wasn’t quite soap. It was scriptless drama with “characters” whose “narrative arcs” were tweaked and massaged into what you'd loosely call "stories" in post-production. The docusoap launched the idea that the public will gladly work on television for sweet Fanny Adams. If there’s one thing you can applaud reality TV for – if there’s just one thing - it’s that it pulled the trigger on the docusoap. So it’s not quite clear what The Savoy is doing on ITV1.

It seems like an aeon ago that we had people who dared to make television series with names like Civilisation or The Ascent of Man. The notion of TV as a forum for vigorous intellectual debate and for taking the philosophical measure of human progress has come to seem almost as quaint as the Reithian newsreader being compelled to wear a dinner suit. I don’t think QI really counts, does it?

Two members of Thet Sambath’s immediate family were murdered during the Khmer Rouge’s time in power in Cambodia. His father was killed when he objected to the organisation's seizure of his property, while his mother was then forced into marriage with a Khmer Rouge militia. She died soon after following complications in childbirth. His older brother, who had witnessed the brutal murder of his father, was also later executed. Enemies of the People, a documentary made with Rob Lemkin, is Sambath's illuminating, admirably restrained insight into a brutal regime.

They have period names in the foreign country we call the past. In last night’s documentary about a brilliant wartime trick practised upon Hitler, we came across a coroner called Sir Bentley Purchase, a love interest called Peternel Hankins and a Welsh tramp with the stirringly patriotic if implausible name of Glyndwr Michael. Charles Cholmondeley, one of the authors of the deception, would even draw attention to the absurd discrepancy between the way his name looked and sounded. More or less the only person in this entire story who didn't sound like a character in a novel was Major Bill Martin, and yet he was entirely fictional. How on earth did the Nazis not smell a rat?