Live: Rocky Horror Show. The Polyphonic Spree, The Forum.

So it was a somewhat blustery Hallowe'en one – same as every year, or so it'd seem. And whilst the Samhain celebration ushering in that eternally damned darker half of the year may occur annually, and with the unerring tedium of the equivalently wretched wallet-voiding guising it entails, down round The Forum a momentous sense of occasion did brood. A one-off exclusive; a "late night double feature." Not since 2007 have Tim DeLaughter's The Polyphonic Spree been about these dank and windswept parts, and indeed in the interim period the boys and girls in the floor-length cassocks have had little to laugh, or for that matter smile about. Financially, keeping fifteen beings on the road has taken its toll; a toll heftier than a Hallowe'en night on Highbury Hill as an assortment of ghouls impudently seek shrapnel. In a rambling outro sermon of sorts, DeLaughter gushes thus: "Thanks for not leaving us! Thanks for staying with us! We're still here – we're funding ourselves." Triumph in adversity maybe, but as he himself concedes: "It's been difficult." There was uncertainty as to whether the show would even take place prior to, as now that it's very much happening they practically implore we "get the merch! Get the merch!" It's one of several insinuations of the band becoming forever more cultish as the cult itself diminishes in number: where Annie Clark once featured, tonight they haul Shelley-styled members of the audience up to be inducted into the great dementia the band bring – a dementia epitomised by a fairly darn flouncy first half comprising the songs of Jim Sharman's The Rocky Horror Picture Show. They may be barely alive, but they're still just about kicking; flinching even, as might a cadaver mere moments into lifelessness. And tonight, the troupe kick the proverbial backside out into touch.

Personally, there's a sense of redemption achieved tonight both for they as a band (in that they've made it over in the first place) and for me as a now quasi-deaf being: my only opportunity to catch them the first time of asking was callously snatched as I wasn't accompanied by the prerequisite parent or guardian. That was 2004, much of which was spent dejected out on the gelid steps of a then November-veiled Astoria. That tells of The 'Spree's sticking power, as well as of how old I now am or at least feel. I've had The Beginning Stages Of... and Together We're Heavy on a sporadic repeat since, although I was beginning to loosen my grasp on the concept of ever clasping the opportunity to witness the hallowed live show. Thus to see them in any state is quite something; to see these two sets, and DeLaughter dressed as a most spectacularly androgynous Dr. Frank-N-Furter by way of Simon Price in the former, well, it's the stuff of finest nightmare.

I'd always deemed DeLaughter's pseudo-sacramental clan to be a far preferable alternative to the melodramatic bombast of Butler's blasted Arcade Fire, although in this first segment they're more redolent of the cast of a Broadway spectacular staged by Ana Matronic, as they haul the veil of the overly earnest right down to the ground. Carl Orff's O Fortuna commences to bellow, conjuring a sense of the suitably histrionic as synthetic gossamer begins to glimmer beneath sanguine lights. It sort of looks like snow, and DeLaughter's scantily clad backing singers sort of look like nymphomaniacal elves, thereby confusing the Hallowe'en aesthetic with one of Christmas. DeLaughter looks haggard as a Grinch, or conversely as those in latex witch masks currently trolling the front doors of north London as he's visibly gotten a little older (as, I say, have I), seemingly less wise, and all the more endearing for it. Damnit Janet is indubitably hammy enough for a premature festive spectacular – high fidelity, hugely ludicrous, but frightfully enjoyable all the same. Time Warp sounds like Boy George, Gloria Gaynor, and ABBA teaming up for a schmaltz-studded Argos ad. Like Slade, it's the stuff of that voidable nether region between Christmas and NYE, whilst Sweet Transvestite is as though Draculean Tom Jones as a caped Tim becomes almost intoxicated by the ebullience of his cross-dressing alter ego; this expertly recited art of persona. Although this may be an exclusive of sorts, one senses this ain't the first time he's come as Tim Curry...

Premature ejaculations of confetti spurt all over the shop to glam throwback tunes and as DeLaughter drawls: "I can make you a man", you're left feeling almost impregnated by the sheer exhilaration of it all. It ought to be enough to have the camp as Christmas adage rechristened, as the feel swings more toward Shaftesbury Avenue than it does Kentish Town. "It's so good to be back. We've missed you guys", DeLaughter professes following on from a strangely impassioned I'm Going Home as The 'Spree extract and redefine the obfuscated emotions of Richards O'Brien and Hartley's original compositioning. Like a trundling theme park ghost train, they never derail from the chronological listing of the '75 soundtrack, as they call at the unabashedly Bowie-esque Super Heroes before going on into that Science Fiction/Double Feature redux, only then vanishing from view. The latter reprise, tinged with melancholy, engenders a discomforting sadness that if initially all but imperceptible, grows tumorously across a short interval.

The last time I witnessed a show sawed quite so starkly in two was when the inimitable, if ultimately fraudulent Andrew W.K. came to this very venue. Blood, guts and exuberance were then all features also, yet whereas Wilkes-Krier spunked his I Get Wet on the opening period The Polyphonic Spree save the indisputable best for later and last. An elastane sheet deep red in shade now spans the stage. Hands gesticulate above; faint silhouettes shuffle upon. Ethio-jazz brass starts up beyond, and the glinting fingers of a scissored hand cut the cloth to break the wait. DeLaughter shears a heart and climbs on through. Even from the opening seconds of Section 14 (Two Thousand Places) they're immediate and inviting all over again. There's a ruddy heart painted onto every garment, as ours flutter as one. It's been too long that they've been away, but we've kept ventricles long since vacant for this moment and to attest to this, amongst the familiar faces profusely thanked throughout are Norwegian pilgrims.

DeLaughter's ringlets and locks may be lone gone, although his charisma remains; his boyish looks unchanged. He is the caring mother of the coterie drenched in blood red, applauding the rampant stabs of cello and tumultuous swoops of string; the faintly martial fanfares and snares that mobilise a jubilant and avidly clapped-along Section 12 (Hold Me Now); the trudging majesty of Section 1 (Have A Day/Celebratory). Maintaining the theatricality of that outré first half, they may have cultivated an excessive reliance on the rawk stuff but when they strike a toned equilibrium between this and their more mellifluous bits – as they do on a fist-thudding Section 8 (Soldier Girl) – then they're a nonpareil even after all these years. Now well over ten, she's as vibrant as she was back then, as is Section 7 (Hanging Around The Day Part 2). Somehow made more polyphonic, it's dusted down for an ebullient rethink that's as invigorating as the undiluted oxygen emitted by those insurmountable trees referenced.

In amongst the thanks, DeLaughter apologises seemingly quite sincerely for their absence although all has since been forgiven in these past fifteen minutes. They're out of the woods and Texan wildernesses now and that, in itself, is more than enough. For I'd feared that they'd perhaps been usurped by all – of Montreal, Wayne Coyne's oft paralleled Flaming Lips, etc. – but these contemporaries have continued to err in tapping into the all-embracive exotericism this particularly idiosyncratic ensemble promote. Tonight they appeal to those with a plastic syringe dangling from either ear; those with stuffed Kermits Sellotaped to the skull; those swathed in shiny white robes. We're all treated as one; as DeLaughter's staunch acolytes, and are showered with lustrous streamer as such. Thus although they may bemoan in unison: "It seems the time has gone away" on a rollicking Section 19 (When the Fool Becomes a King), their time is now. It's short, and sweet, and as DeLaughter rabidly yodels: "Let's keep going!" towards the end of an appositely uplifting Section 9 (Light & Day/Reach For The Sun), the end is nigh.

They remain the only cult I'd consider joining, and with a new fan-funded record expected next year there may be more where all this distilled joy came from – this end may not yet be theirs. But that negligible tumour of sadness has now swelled into a thoroughly depressing thought. That, as they approach their 10th anniversary as a band, that which they do so unfailingly keenly may not be enough to ensure survival. Undoubtedly, in here harking back to the pasts of Sharman's '75 and their own '00s they jumble together a present-day memory sure to plague the mind for a long while yet. However, it's their collective future that remains terrifyingly, and with that tragically unstable. It seems, on this Hallowe'en soirée, about as precarious as a ritualistic jig on the ridge of a bloody knife. Nonetheless even in these latter stages of... they remain an act of utmost integrity worth rejoicing in whilst it lasts...