YOU can see how it probably happened.

Channel 4 had a late-night brainstorming session to “think outside the box”.

Hours of nothing, then suddenly one bright spark pipes up: “Let’s think INSIDE the box. Put couples in one. They could have sex and everything!”

So it was that Sex Box entered the world kicking and screaming.

It’s Phillip Schofield’s Cube minus the inconvenience of actually being able to see and hear what’s going on inside.

A pair of “very brave volunteers” walks in, has nookie and, explains host Mariella Frostrup: “Immediately afterwards talk frankly about what they did, to me, a panel of sex experts and our studio audience.”

Not before a commercial break though.

As for talking frankly, one lot clammed up the moment they were asked for details.

So you may be wondering, reasonably, what was the point.

Well, apparently, there has “never been a greater need to talk about sex”, a statement disproved instantly by panellist Tracey Cox: “When the internet first came out it was all porn but now there’s tonnes of good information out there.”

Frostrup insisted: “A lot of people might think getting couples to have sex is a TV gimmick,” (surely not), “but there’s a lot of research to say...”

Yeah, yeah. Whatever.

Truth is C4 made this solely to trend on Twitter, today’s unreliable barometer of a programme’s success.

It was just a giggle, as highlighted by the box’s hilarious traffic light system indicating when the deed is done.

In fact, they could have had more fun with it.

When one couple recalled: “We took our clothes off, a bit of foreplay and then went into it,” and expert Phillip Hodson asked: “Into...?” Frostrup should have had a whiteboard and marker and said: “Time we had that chat about the birds and the bees, Phil.”

Forming part of C4’s Campaign For Real Sex season, I so wanted to see a heavily bearded man in a woolly jumper with a love for cask ale looking lost in the audience after misreading the memo from CAMRA.

The couples ticked so many boxes – straight, gay, lesbian, wheelchair-bound – that I half expected a two-headed midget wearing a gimp mask and nipple clamps to emerge.

And the host could have followed Cox suggesting: “A simple way to keep things going sexually long term is to change one thing every time,” by asking: “The sheets?”

Frostrup did, however, steer events in the humorous manner intended and, in so doing, teed up a lightning bolt TV moment.

During the second ad break, after gay pair Matt and John exited the box looking flustered, came the voice of Rob Brydon.

“B&Q can help you say goodbye to your unloved rooms, the stain that has no shame and the love nest that’s lost its allure. You can do it, Britain. Now is the time to man up your sex cave.”

You can’t make it up.

This week’s Couch Potato Spudulikes...

The inspirational Pride of Britain Awards (aka Britain’s Got Talent’s open-mic auditions).

BBC2’s The Wrong Mans delivering week after week.

Claire Danes and Mandy Patinkin in C4’s Homeland, which returned at a slower-than-breakneck speed but is still the best thing on TV right now.

Tony Jacklin’s plus fours, Sophie Ellis-Bextor’s celebratory Charleston and Mark Benton, in a hallucinogenic shirt, giving the salsa his all to Bom Bom, by Sam and the Womp, on Strictly.

C5 following Fat For Cash, which ironically could only be watched on an empty stomach, with the Health Lottery draw.

And The One Show’s Alex Jones fluffing her Autocue at the best possible moment: “According to a new report, young people in England and Northern Ireland have some of the worst reading and writing maths skills... AND maths skills of the developed world, behind Estonia, Czech Republic and Poland.”

But not Wales, eh, Alex?

This week’s Couch Potato Spuduhates...

Corrie’s Nick Tilsley grumping his way into a personality transplant, plus the absence of Jeremy Kyle to reveal his imminent paternity test results.

ITV2 magic show Tricked going about like Derren Brown and Dynamo never happened.

The disappointment Fat For Cash wasn’t a version of The Bachelor featuring 30 enormous chubbers throwing themselves at former Wimbledon champion Pat Cash.

C4 thinking it needed a wordplay panel show with David Mitchell and Micky Flanagan, Was It Something I Said? (Yes. Yes it was. So rearrange these words into the correct order: Off. Clear.) And arty farty Julian Fellowes on The One Show: “When you’re writing a show like Downton, you’ve got to limit the number of people you’re trying to service in a narrative sense.”

Yeah, or you could just chuck in a rape scene from nowhere to get attention.