Pants, Dundee Rep Theatre, Dundee

As the arrival of Chitty Chitty Bang Bang prompts a flurry of hand-wringing punditry concerning the West End's paucity of decent new musicals, in Scotland that ginger-headed theatrical polymath, Forbes Masson – actor, writer, director, lyricist – has turned out three such shows in as many years. Combining a manically subversive spin on the Scottish variety tradition with irreverent contemporary satire, outlandish theatrical imagination and lashings of effervescent wordplay, both his previous offerings, 1999's Stiff! and last year's Mince? (the latter a Best Musical nominee in the Barclay's TMA Awards) were big hits with audiences and critics – even on a regional rep's budget, as opposed to a Lloyd Webber's.

Where Stiff! took a millennial-Faustian look at our fears and taboos surrounding death, and Mince? located a storyline involving the meat trade and senile dementia inside the mind of an advertising jingle-writer, Pants adopts a (relatively) more straightforward narrative framework. It tells the story of Scottish wannabe rock-god Rikki Rintoul, during his nearly-was nearly-heyday and during the dismal professional and emotional doldrums of 20 years later.

Two separate casts portray him and his band, the Pants, within these alternating and overlapping timescales, both set in the same dingy loft-cum-rehearsal room in Rikki's native Falkirk – a routine byword for nowheresville small Scottish towns, as in the Pants' punk-phase number, "Get to Falkirk!".

There prove to be plenty of phases in the Pants' career, such as it is, as Rikki – the self-styled "McChameleon of Rock" – determinedly hitches their wagon to every passing musical trend from glam rock to the new romantics. There's even a hilarious, Abba-esque Eurovision attempt with "Bannockburn", which works as both a send-up of identikit tweenie heroines and a sideswipe at Pop Idol.

One obvious conclusion to draw from the resulting string of lavishly camped-up yet sharply observed musical sequences is that the designers – in this case, Tom Piper – must have a ball working on Masson's shows. The songs' appeal goes beyond the visual, however, with Masson again displaying his lively facility for sly verbal parody, deadpan kitsch and undercutting rhymes.

As with the two earlier musicals, Masson makes a bold attempt to interweave all this boisterous wit and vulgarity with much darker strains, from the simmering sexual and professional jealousies within the band, to the unmitigated desolation of Rikki's whisky-sodden present-day existence. In other respects, though, Pants is notably less extravagant in its compass than its predecessors, and suffers from being set in a milieu that has virtually been parodied to death. It might once have provided easy targets, but the world of rock and pop now frequently commodifies parody, so that it becomes an element of the product itself. It's become increasingly tricky, then, to mint fresh comic coinage from such well-worn base material.

On the other hand, Masson set himself a formidably high standard to match with his previous shows. Judged on its own terms, Pants still makes for a rollicking good night out, with characteristically committed and vigorous performances from the Dundee Rep Theatre's resident company.

To 4 May (01382 223530)