Sheridan Smith doesn’t quite bounce on stage at the top of Joseph and the Amazing Technicolor Dreamcoat shouting ‘Hiya kids, do you wanna be in my gang?’ but that’s the sole restraint that stops this bombastic production from being a full-blown pantomime.

The woman seated next to me politely asked ‘have you seen this show before’ and I said ‘no – but I’ve read the book’. ‘Oooh’, she said, ‘is there a book? When did that come out?’ blithely crediting Lloyd Webber with the authorship of Genesis as well as his multitude of other achievements.

Two things emerge from this exercise: one is the fact that if you have the right marketing and access to the Palladium box office database you can sell not just corn in Egypt but a second annual outing to your panto customers. Believe me, if I had grandkids and six hundred quid to splash up the wall to take them out for the evening, I’d buy their affection with it.

The other is that Jac Yarrow, plucked pre-graduation from Arts Ed to star as Joseph, is a genuine gold-plated find.

He is a charming and attractive singer without American inflections and in splendid crescendo delivers energy and pathos without lurching into a ‘rock voice’. ‘Close Every Door’ is the undoubted highlight of the show, and a rare moment of actual drama and emotion.

He is perfect in the role, a warm and naturalistic antidote to Smith’s chavvy cheerleader dressed from the Canaan branch of Primark.

I do think her inspiration comes from Victoria Wood’s energetic aerobic instructor ‘Hayley Bailey’.

You could cavil that with an ensemble of sixteen and a swathe of abstract set, the show doesn’t quite fill the Palladium stage, that hiring such a large troupe of children is both cost-saving and cheesy, that the songs are a predictable rota of pastiche, that as Pharaoh Jason Donovan’s voice sounds harsh and he’s not really a very good Elvis impersonator – but none of this really matters as the production’s virtually sold out for this year’s school holidays, and tentatively booked in for next. Talk about a Prophet Motive …

There’s love in the house, and a constantly breaking wave of affection for its star turn. If Smith can put so many bums on so many seats, maybe she is worth fifty grand a week.

Sorry, Jason, didn’t you know that?

until 8 September.