TV preview, Ross Kemp: Libya's Migrant Hell (Sky 1, Tuesday 9pm): TV hardman takes on a more serious subject

Plus SS-GB (BBC1, Sunday 9pm); This Country (BBC1, Saturday 11.40pm, BBC3/iPlayer, Wednesday)

Ross Kemp has made a powerful film about the plight of migrants in Lybia (Sky)

I know that a programme with the title Ross Kemp: Libya’s Living Hell is an unlikely candidate for TV highlight of the week, but if you do steel yourself to get through it you will be glad you did so.

To be frank, the sheer scale of human suffering in the hour-long documentary transcends the usual absurdities of Kemp’s hard-man routine. You have to take him, and the genuinely brave work he has done here, seriously, following the most desperate migrants traversing desert and sea, evading gangs, suffering rape, beatings and theft, and being sickening exploitation by the people smugglers. We even get to meet a smuggler, awaiting trial in Libya, and see what lies behind the greed and cruelty.

As Kemp says in this powerful film, whatever your views on the rights and wrongs of migration, of rescuing migrants and the EU and UK immigration policy, we have a moral duty to at least acknowledge the full horror of what is unfolding in the Mediterranean and, much less appreciated, the vast distances of the Sahara, where the journey towards a better life and away from poverty or persecution can be even more dangerous than the sea crossing (if they get that far).

The sight of so pathetic and, frankly, doomed human beings is familiar from the news. Rarely to do we hear their voices at first hand, as we do here. Kemp and his team gained remarkable access to the gangs and their victims, most depressing of all in the “detention camps” run by what passes for the Libyan authorities. The one that is supposed to look after women is especially galling, with 200 women confined to one overcrowded shed, eating meagre rations, sleeping, suffering beatings, giving birth and dying in cramped unsanitary conditions, and with little contact whatsoever with their families or the outside world. They want to go home; their own countries don’t seem interested in having them back.

Libya, since the West abandoned it after its (Western-backed) revolution, has seen its economy collapse, with oil production, which promised to convert it into a regional superpower in Colonel Gaddafi’s time, at record lows. The average Libyan earns about £400 a month; a people-smuggler can profit to the tune of about £25,000 a week. Hence the trade.

Libya today has three governments, about 40 tribal fiefdoms, some Isis training camps and virtually no Western aid agencies or medical assistance. It is a failed state, and no wonder it is a humanitarian disaster. The voices of these pitiful people, the most miserable of all women sold into prostitution to pay for their own journeys, coming from Nigeria, Niger, Ivory Coast, Gambia, Sudan, Somalia and a host of other failing and failed states they give their different motives for taking such a huge risk – often to escape war or Boko Haram, but not always, many simply wanting a better life for themselves and their children. Kemp mostly stays off the politics, but he lays part of the blame on those Western governments that let Libya rot once Gaddafi was ousted, a sentiment that is hard to deny. Whether the EU’s flotilla of search and rescue vessels are a “pull factor” or not in the migrant crisis is a debate for another day.

Alternative history – the “what ifs” that the past left behind – has always been absorbing, and no parallel universe more intriguing than the one where the Germans succeeded in occupying Britain in 1940. Len Deighton thought it so engrossing a scenario that he wrote a novel based on that very premise, the cover featuring Hitler’s mug on a British postage stamp.

We’ve had plenty of documentaries, books and the odd fictional treatment, but none come close to the period detail and stunning CGI work in SS-GB, a BBC dramatisation complete with a part-bombed out Buckingham Palace festooned with swastikas. There isn’t, in truth, much mystery about what might have happened, broadly. Winston Churchill might have talked about a powerful guerrilla force taking to the hills to hit and run the Germans, and a doughty resistance being fought on every beach and street, but the experience of other countries and territories – even those, such as Yugoslavia or Norway that did summon up an effective resistance – was not like that. In most of their occupied territories the Germans were resented by most, tolerated by many, collaborated with by some, and fought by a few. In the Channel Islands, the only British “home” territory to be occupied by the Nazis, life went on, with some quiet heroism and some quiet betrayals. Even though fictional, Deighton’s copper working under SS auspices irresistibly puts the question in one’s mind: what would you have done?

Once again I have to urge you to catch This Country, broadcast late on Saturday nights on BBC1, and available week by week on the iPlayer/BBC 3. The latest features some terrifying scenes of tattooing, coincidentally featuring an especially comical-looking rendition of Ross Kemp. And, with that, I have come full circle.