Last Night's TV: The Real Life on Mars, BBC4; Superhuman: World's Smallest People, ITV1

Even by television's self-referential and indeed self-reverential standards, a TV programme about a TV programme inspired by a TV programme is stretching things a little, and I duly approached The Real Life on Mars with caution, as a police officer in 1973 might have approached an abandoned Aer Lingus rucksack in a London street, or as a Rastafarian in a London street might have approached a police officer in 1973.

As it turned out, my apprehension was groundless. The Real Life on Mars was an intelligent and enlightening documentary about the ways in which cop dramas down the years have reflected, and on occasion influenced, developments in policing. This was the opening salvo in BBC4's new Brit Cop season, and as one of those invited to a working men's club in the East End of London a couple of months ago, and asked to talk coherently in front of a camera about Z Cars and The Sweeney, I suppose I should declare some sort of interest. Not that I spotted myself on last night's programme. Maybe I wasn't coherent enough, or maybe my clunky aperçus have been stored for later in the season.

Most of the talking heads here were retired detectives, wheeled out to offer their thoughts on the authenticity of 1970s policing as interpreted by Life on Mars and before it, The Sweeney. Their views varied. For former Detective Chief Inspector Steve Crimmins, an adviser on Life on Mars, the brutal techniques of the 1970s, not to mention the sexism, racism and homophobia rampant in most police stations at the time, were actually toned down in the form of Philip Glenister's DCI Gene Hunt and his colleagues. Crimmins had an unlikely ally in Paddy Hill, one of the six people wrongfully convicted of the Birmingham pub bombings in 1974. Hill's only quibble with Life on Mars was that "it doesn't go far enough in respect of the brutality and the violence".

On the other hand, Bob Thorogood, who served in the Northamptonshire constabulary in the 1970s, reckoned that The Sweeney, which Life on Mars evoked with such unsubtle brilliance, harmed the police immeasurably and was one of the reasons why public respect for the police, pretty watertight at the end of the 1960s, had sprung so many leaks by the start of the 1980s. He insisted that the gun-toting, punch-throwing methods of detectives Regan and Carter in The Sweeney gave people a skewed and damaging view of the police, and even ex-DCI Jackie Malton, the Flying Squad officer who was the model for Jane Tennison in Prime Suspect, observed that she never saw her colleagues beating anyone up. Which, I suppose, is not to say that they didn't.

Nobody claimed that prejudices weren't rife in the police force in the 1970s. Maybe they still are, but these days they cannot be so casually expressed. A couple of retired female Metropolitan Police officers recalled how they were initiated into the CID by having their underwear torn down and their bottoms rubber-stamped. Outnumbered by men 25 to 1 in 1975, they couldn't walk up the stairs in the police station but had to use the lift, to prevent male colleagues from looking up their skirts. And David Michael, who in 1972 had been one of only 11 black officers out of 28,000, explained how he simply used to smile whether comments aimed at him were innocuous or offensive, so that nobody could see when he was smarting. Times have changed, but perhaps not as much as we like to congratulate ourselves that they have. Michael assured the programme that the Met is still bedevilled by the Life on Mars mindset, as represented by the Hunt acolyte who on being assigned a black colleague said, "First women, now a coloured, what's going to be next... dwarfs?"

All of which brings me neatly to Superhuman: World's Smallest People, a documentary about short people of various shapes and sizes, billed as an attempt to shed light on their attempts to find happiness, although it could not quite shed the unfortunate whiff of a freak show.

About 18 months ago, the lavishly garlanded documentary film-maker Jane Treays made a film about primordial dwarfs that explained those lavish garlands. It was shot through with compassion and finely tuned sensibilities. David Donnelly's film lacked those qualities, possibly because he tried to cram in too much. The ambition of He Ping Ping, from Inner Mongolia, to be authorised by the Guinness people as the world's shortest man, was surely worth a programme on its own, without the competing diversions of Britain's shortest man (who works for Customs and Excise in Southampton) and a 3ft 6in stand-up comedian from Las Vegas called Tanya, not to mention a visit to the Dwarf Athletic Association Games in Birmingham.

We didn't find out how He Ping Ping's life changed when he got the official sanction he craved, or much about him at all, beyond his fondness for cigarettes, which he smokes at the rate of 30 a day, perhaps hoping to stunt his growth.