A declaration: I haven’t seen the film. Let alone read the novel. It might help if I had, since there seems to be a reasonable, implicit assumption of prior knowledge. So, if you’re thinking of seeing it, maybe take up studies in Legally Blonde 101.

The first half is as flat as the Nullarbor. The only thing that really stands out, despite very competent performances, is the production design, appropriated from Broadway. The number of scene and set changes is phenomenal; quite conceivably setting some kind of record. And the execution is brilliant. But we have to wait until the second act to get any semblance of wit, genuine humour, heart or panache.

Frankly, at just over two-and-a-half hours, you could easily cut, say, an hour, without blinking. And none would notice. Nothing of substance need be lost. It’d be a much better musical as a result. The book’s by Heather Hach, music and lyrics by Laurence O’Keefe and Nell Benjamin. Yeah, exactly. Until LB, they hadn’t exactly set the world on fire. But while much of their music’s wildly derivative (let’s be kind and chalk it up to homage) and genre-scanning, some is genuinely stirring. Likewise, while much of the story is also-ran and lyrics throwaway, there is a heart, inasmuch as the values exemplified (hell, even Shakespeare is invoked) and the price of the tickets is almost covered with one song in Is He Gay, Or European?

“There, right there! Look at that tanned, well-tended skin, look at the killer shape he’s in, look at that slightly stubbly chin, oh please, he’s gay, totally gay!”

In case, like me, the LB phenomenon has escaped you, here’s your primer. Elle Woods is a sorority girl, through and through. Life, in Malibu, is a beach. And everything in Elle’s wardrobe is as pink as the sunset. She’s banking on a wedding proposal from Warner, her boys, but he comes through with a break-up instead. A simple misunderstanding. He’s perplexed when she appears peeved. He racks off to Harvard. She follows, enrolling, like him, in law school. She and her bitches’ cheerleader-style presentation clinches admission. After all, an essay’s so boring. Long story short, Elle cuts it not just as LB, but LLB, successfully defending a liposuctioned gym junkie in a murder trial, earning respect, admiration and a better, if sartorially retarded, bloke.

Lucy Durack stars as Elle. What’s not to like? Well, on this occasion, there’s one or two things. First of all, much of the time, I couldn’t understand her; though I reckon this is down to sound. Second of all, while the nasality and twang is totally in character, I would’ve preferred it be confined to dialogue and eschewed for the songs, as it becomes almost unbearably grating after a time. Rob Mills seems to have co-billing, yet his role is comparatively modest and, though his vocals are attractive, he lacks power and that certain something; the much-touted X-factor. David Harris is more compelling as Emmett: both his singing and acting command attention.

But, for mine, the most shining talent comes from a little further down the cast list. Helen Dallimore is terrific as Paulette, the unlucky-in-love hairdresser whose bulldog has been held hostage by her ex. But perhaps the biggest surprise, especially given her relative lack of experience, is the statuesque Erika Heynatz, as Brooke Wyndham, a kind of Jane Fonda meets Kim Kardashian. Her voice was strong and clear; her stage presence very much felt.

Cameron Daddo did his best, I guess, but neither his singing nor his acting really convinced. He’s tall enough, yet not big enough for this role. Ali Calder was good, as the unlikeable Vivienne. The so-called Greek chorus was shimmeringly vibrant, both in terms of song and dance. To name but one among them, Chloe Zuel showed real promise. Mike Snell was popular as himbo, Kyle and showed the versatility of his talent by doubling as Grandmaster Chad and Dewey. Andrew Ronay-Jenkings was a treat, as pool boy Carlos and Elenoa Rokobaro’s sentence, as the judge, was a just one. Jerry Mitchell’s choreography is wonderful and direction admirable.

This is a musical that made up to a million dollars a week on Broadway. There’s no accounting for taste. There’s only accounting for accounting. If you can, get HalfTix and turn up for the second half. It’s the most fun you can have and still be brunette.

The details: Legally Blonde plays the Lyric Theatre, booking until December 16. Tickets via Ticketmaster.