"Everyone is beautiful when they dance,” oozes the ballroom MC in the midst of a competition that reveals just how un-beautiful terpsichorean people can be when seriously challenged by other dancers, or by anyone radical enough to try to dance to a different tune. Yes, Strictly Ballroom the 1992 film has become Strictly Ballroom the Musical – premiered in Sydney last weekend with Kylie Minogue in attendance – as it was always destined to be.

Andrew Lloyd Webber and Ben Elton's musical was first seen in the West End in 2000, where it received mixed reviews and ran for just under a year. In 2009-10, they reworked the show for productions in Canada and South Africa under the title The Boys in the Photograph, and now it receives its first London revival in Union Theatre. Although it has the original title, Lotte Wakeham's spirited and thoroughly enjoyable production is essentially the revised version, with its more uplifting ending.

The “fantasy” Riviera conjured by designer Peter McKintosh for the West End premiere of Dirty Rotten Scoundrels - the Musical is pretty much an extension of the Savoy Theatre’s shining Art Deco auditorium, its sleek angular segments gliding into position like they too have been choreographed by director/choreographer Jerry Mitchell. So it looks devilishly good and it smells of money and deception. Which (as those of you have seen the semi-classic movie will know) is precisely what this expensively upholstered romp is all about.

The names have been changed to protect the guilty but half the fun of I Can’t Sing! - the so-called X-Factor musical - lies in the relentless spoofing of a show we love to hate and a format so unremittingly predictable that its contestants, judges, and host now read like characters from a, well, musical.

For those who haven't seen it, the funny face of the title belongs to Audrey Hepburn. As preposterous as that seems for someone so iconically gorgeous and although when others fail to notice her beauty it seems insane, Hepburn was famously insecure, so when her character Jo Stockton says, "I have no illusions about my looks, I think my face is funny" it doesn't sound insincere.

The most ambitious musicals spring from the most unlikely sources – you need go no further than Stephen Sondheim to establish that – but turning those musicals from novelty into living, breathing, involving experiences requires very special talent. Back to Mr Sondheim. Everyone who writes in this medium owes him a huge debt of gratitude but some – like composer/lyricist Gwyneth Herbert, the fresh voice behind The A-Z of Mrs P – would seem to have evolved almost in spite of him, from another place altogether.

Showboys will be boys – gym-bunny sailors, in this instance – as well as sisters, cousins, aunts, captain’s daughters and bumboat women. We know the ropes by now for Sasha Regan’s all-male Gilbert and Sullivan: a loving attempt to recreate, she says, the innocence of musical theatre in same-sex schools (mine, for which I played Sir Joseph Porter with a supporting army or navy of recorders, two cellos and piano, was mixed).

“God,” wrote Stephen Sondheim, “is in the details.” Of course, he didn’t actually coin the phrase but throughout his published collections of lyrics he cites it as one of his three guiding principles. But to witness detail you need to be up close. Last seen on Broadway in the 1,058-seat Barrymore Theatre, Putting It Together felt overblown and strained. In the 312-seat St James Theatre, its strengths – the delights of a deftly interwoven selection of 32 Sondheim songs – leap into focus thanks to a quintet of deliciously detailed performances.

Playgoers could be forgiven for thinking that they were seeing double during much of 2013. No sooner had you sat through Ian Rickson's dazzling revival of Old Times once before you returned again to watch its peerless pair of actresses, Kristin Scott Thomas and Lia Williams, swap roles. Similarly, Ben Whishaw had barely shed his Peter Pan-related persona as the male half of John Logan's Peter and Alice before lending his whiplash authority to the revival of Jez Butterworth's Mojo.

Unlikely subjects can make for great musicals. (Assassins, anyone?). Just as great subjects can make for terrible ones (the Broadway Breakfast at Tiffany’s comes to mind). Sadly Andrew Lloyd Webber’s latest project can’t redeem itself on either count. An awkward story allied with a treatment that veers from unexciting to embarrassingly bad, the only marvel here is how it ever made it past the workshop stage. I would have hated Stephen Ward if I hadn’t been so numbed by boredom that I couldn’t muster emotion even approaching that intensity.