The most alarming sight on such a first night as this is the “lamb to the slaughter”, a contestant who on seeing his or her housemates flails, an expression of horror revealing sudden realisation of a horrible mistake.

Celebrity BB seems like a good idea: your career’s over, or it hasn’t started, so why not give the mother of all reality shows a shot. But then the freakiness of it subsumes you and you’re scrawling madnesses on blackboards (Vanessa Feltz) or pretending to be a cat in a shiny leotard lapping milk from the hand of Dennis Waterman’s ex (George Galloway).

At this early stage, this year’s lamb is Danielle Lloyd, a former Miss Great Britain. Lloyd seemed perky enough but the BB crowd — sensitive to any inner ugliness and prepared to show it with concerted booing — turned on her. She introduced herself to Jermaine Jackson who clearly hadn’t any idea who Lloyd was (his grimace as set as granite). He expected her to know who he was so didn’t introduce himself. And so they stood there, hideously frozen. He had rather creepily suggested that his brother Michael, although in Las Vegas, “can see everything”.

In a masterstroke, the producers ratcheted up the dysfunction quotient by chucking in Ken Russell, who bounded down the red carpet like a giant strawberry bonbon singing Singing in the Rain. He swore, almost fell over and produced the most poignant line of the night. Who was he? Lloyd asked. “I’m an old English film director from way back,” he said. He was faced with utter incomprehension and your heart sank for him.

This skewed notion of lost or desired “celebrity” is the combustible element: each contestant’s entry was prefaced with a video diary showing what they are famous for or who they are. They can be utterly inoffensive, like Jo O’Meara (from S Club 7 to dog breeding) and Ian Watkins (“H” from Steps who came out, to absolutely no surprise, in The Sun yesterday). Shilpa Shetty was so beautiful and classy Davina found herself helping the Bollywood star up the steps.

Just why are they doing this, you think, then dismiss any deeper meditation.

It's genius panto, for sure: the A Team’s Dirk Benedict played the washed-up roué to perfection with his care-in-the-community jeans, puffing on a cigar and reeking of ham.

Then there were the contestants whose smiles were a little too wide, or whose behaviour was so contrived you doubted their sanity and worried for their housemates’ safety. Leo Sayer barrelled in, ever the demented troll. Donny Tourette is this year’s rocker-boy. He swaggered, effing and showing the finger (very Pete Doherty), and even dared to diss Davina, then ruined the whole bad-boy thing by greeting Leo Sayer with a great big luvvie hug.

Best of all was Cleo Rocos, Kenny Everett’s busty former sidekick, who said she was after OIL — “old, rich and loaded”. She claimed to be “a happy doodle on God’s telephone pad”. Go Cleo! Together, finally, they seemed like a roiling, discordant orchestra, all babbling. Their complement was replete with Carole Malone, a journalist who hopes to get a scoop, but if the show works properly, she’ll be the first to crack before the week is out.

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