Asharp-suited Rupert Everett talking openly and honestly about sex is pretty refreshing. Rupert, you see, is at the helm of Channel Four’s two-part Love For Sale (next episode is on Monday, 10pm) and has just been online to give us a sweeping vista of the male prostitutes on offer Stateside. He’s called one – British Beef Bruno – who pops over to chat, and flirt with Rupert which, surprisingly, feels neither odd nor cringey.

In case all this sounds jokey or inappropriate, though, don’t let Everett’s camp familiarity with his subjects fool you. He is the vital injection of honesty and mesmerising intelligence this subject needs. And it is utterly, utterly spellbinding stuff.

The sex trade is the oldest profession, as no one needs reminding, though Rupert does, stylishly, referencing Mary Magdalene, the art of Toulouse Lautrec and transactions since the beginning of time, such as marriage. Sex as collateral, he explains, is how the world turns: there’s no point pretending otherwise. It’s not a bad position to start from if you’re looking to explore an industry whose workforce are treated as sluts, victims and criminals thanks to layer upon layer of hypocrisy, fury and taboo.

Rupert asks the men and women on the street, from the Exeter housewife to the Liverpool street-walker via the Brazilian £700-an-hour Mayfair escort and young Tel Aviv rentboy, about their jobs.

And what Rupert brings to the party as writer and presenter is brutal honesty, debonair charm and heartfelt passion, resulting in one of the most beautifully startling pieces of telly you’ll see.

An actor, a gay man, a friend to several prostitutes (“those sweet, funny hags, absolutely adorable, courageous”) and occasional customer of the sex industry who has also turned tricks himself, it is fair to say Rupert breaks down barriers in a way that, say, David Attenborough might not.

The aforementioned Bruno tells us about his lot as a hot, savvy in-demand male escort who has travelled the world and reveals eight friends of his have committed suicide in the last year.

You do not see interviews this intimate and revealing very often, but Everett delivers them thick and fast.

And despite the darkness lurking in life’s seedy underside, he is funny, too.

Love For Sale might sound voyeuristic, but this programme’s mission is to unravel the stigma that imprisons prostitutes in a murky world.

In the brightly efficient call centre of one suburban madam’s escort agency (complete with notes about clients on the whiteboard; whether they are “rough”, a timewaster or simply “the most boring man in Britain”), it’s clear these women are in unnecessary danger. The enterprising former working girl knows no politician is tempted to touch the ban on brothels in the Sexual Offences Act 1956. But taking a fresh, less British look at this law would mean her employees (teachers, care workers and, of course, that staple recruitment sector: single mums) would not be forced to go singly into the houses and cars of sometimes violent strangers.

Having seen a close friend – transsexual Lychee – killed in the Bois de Boulogne region of Paris in the 1970s, Rupert understands the risky game of sex among the shunned and shamed. You are unlikely to see a slice of television more heartbreakingly surreal than him and a gorgeously slinky transgender hooker belting Elton John’s Sorry Seems To be The Hardest Word – and that’s a money-back guarantee.