Hannibal Lecter once asked himself as he scoured the faces of a crowd at a torture-instrument exhibition in Florence: “What still slaps the clammy flab of our submissive consciousness hard enough to get our attention?”

One answer came in 60 Days on the Streets (Channel 4), a documentary from the ex-army captain and seasoned explorer Ed Stafford. It details (in the first of three parts – subsequent episodes see him visit London and Glasgow) his time spent living homeless in Manchester. If the Hannibal quote seems too Grand Guignol in the circumstances, you can’t have been paying attention to Stafford’s deep dive into the underworld of Britain’s northern capital city. Spice addicts stand drooping in the streets like zombies while passers by – well, pass by, as oblivious to them as they temporarily and presumably blissfully are to the world. Knock-down, drag-out fights play out against flickering lights in underpasses, or in plain daylight, leaving blood spatters on the pavement. Outside her carefully constructed shelter against a wall, a woman dries her socks on the door of the mobile police unit abutting her new non-home.

Sixty days is long enough to get anyone’s attention, even without Stafford’s evident commitment to the project. He eats out of bins, washes in the toilet bowls of cafes because sinks are always outside the cubicles, where you can’t strip off and scrub your increasingly itchy bits. This first stretch in Manchester gives Stafford, and us, a chance to get to know people, the rhythm of life on the streets and its insidious effects. It is sometimes counterintuitive; by the end, Stafford notes that the initial shock and daily discomfort have receded and he is beginning to enjoy the mindless and absolute freedom from responsibility and timetables that itinerant life offers.

Of course, even if he is begging (or “grafting” as his new companions call it) he is unavoidably still living off vast social capital. He does not have the shadowy, jagged backstories of all those he meets. Dina, who offers him a biscuit and a shared bed for the night (“No funny business – I’ll punch your fucking face in!”), who has a drug addiction and six children living with their dad (“My first love, when I was 15”), was 13 when her parents split up and “everything went pear-shaped. If I’d been pushed in the right direction, like a child should be pushed … I’d have made something with my life.”

Twenty-six-year-old Jeff says the council deemed him intentionally homeless when he was evicted while hospitalised after a suicide attempt. He is good at hustling for money. “Sitting with a cup is like waiting for God to drop fortune in your hand. You need to be proactive.” It gradually becomes clear that Jeff is not the relatively clean-living, optimistic, newly homeless figure he at first seemed. He is an addict who began working for a drug gang as a child, first tried heroin when he was 13 and has had a habit ever since. Stafford, in a slightly jarring moment, seems to write him off for the deception when others might have tried to imagine the life of a drug-running child and adolescent user and marvelled that he was still standing. He also seems rather too easily convinced by one alcoholic companion’s drunken insistence that he is happy on the streets (which is not to say the companion might not be so, but it was worthy of further consideration, if only to preclude its easy adoption by people looking to cut council resources or husband general compassion further).

But these were tiny quibbles in an hour of genuinely revelatory television that managed to burrow several layers deeper than the usual superficial scrapings we are used to. We saw the prevalence and sensed the irresistibility of drugs. We saw the physical violence among homeless people, the verbal abuse and pettily cruel humiliations heaped upon them by the public. “You’re a lazy fucker!” shouts one, with a venom most of us couldn’t muster if we had just seen someone kick a kitten. “You need smacking and putting down!” One morning, Stafford is woken from his semi-sleep in another piss-ridden doorway by a street cleaner (apparently deliberately) soaking his sleeping bag with his hose.

It is not Stafford’s remit – or, you suspect, his way – to linger on the wider questions like what makes someone do that, or how attitudes towards the poor and vulnerable are shaped by our own experiences, by what we are told by the government, by the portraits painted in the media. But his programme is so penetrating, the stories and scenes so vivid, the whole thing done with such devotion that it succeeds in making viewers pose them themselves. The clammy flab is slapped. Collective consciousness, let us hope, awakes.