Credit: Marc Brenner

Like J K Huysmans À rebours smashed into an episode of Black Books, Richard Greenberg’s riff on the life of the reclusive Collyer Brothers is a louche but unsettling piece. An eccentric pair who skirted New York society with glimmers of brilliance before collapsing into a hermetic, hoarding existence, the Collyer brothers’ true story glows only faintly through Greenberg’s comic but forced drama, which elsewhere relies for its illumination on two exquisite central performances.

‘Star vehicle’ suggests a sense of movement and momentum, so perhaps it’s truer to say that The Dazzle provides a pedestal, or a display case for the talents of Andrew Scott and David Dawson as the two brothers clinging to one another in the decaying splendour of their apartment and their minds.

Scott is the outwardly brilliant musical prodigy, Langley; an ear tuned like Roderick Usher’s, and with a temperament as brittle, like a frozen piano string. Dawson is the less assuming, more socially competent, and ultimately more intriguing Homer, who has developed a kind of Munchausen syndrome by proxy, acting at first as his brother’s sort-of-agent, then his carer, then even his gaoler. As the years go by they goad each other into ever more extravagant forms of lethargy and eccentricity. They squabble and meander, they morph through permutations of dependence and reciprocity – they become a dozen double acts, they echo every form of brotherly, parental and even platonically romantic kind of coupling.

Greenberg’s script is filled with sparkling exchanges and baroque turns of phrase. Scott delights in Langley’s drawling absurdities and fierce ticks, while Dawson looks out into the middle-distance, pompous and stately. Dawson is the Marwood to Scott’s Withnail, he is the Manny to his Bernard, the Harold to his Albert. You could watch them forever. They have the intrinsically fascinating quality of mutual hatred mingled with mutual love; they rot and drown together in the most elaborate but repetitious patterns.

But like Steptoe & Son in the films, Withnail & I in some of that stuff in the Lake’s, Bernard and Manny in the entirety of Series 3 of Black Books, Langley and Homer are only really convincing when they’re doing nothing. Greenberg hasn’t made any great attempt to reach the truth at the heart of the Collyer brothers, or the significance of their plight, they are only the springboard for some excellent writing and acting. When The Dazzle tries for something resembling tension, or dramatic structure, it all begins to tarnish.

Joanna Vanderham is given an almost inexcusably duff time as love-interest Milly Ashmore, present largely to hold the gents’ coats while they piss on each other, and provide some loose scaffolding to the play. The puffed-up question of her marriage to Langley gives her nothing to do except flap around a character who becomes markedly less convincing and interesting when fawned over. Her re-appearance in the second act, with its echo of the fallen woman of mid-19th century sensationalism, is almost insulting. Vanderham is doing her best, but in the play as on its poster, she’s invisible opposite two strutting, self-consciously fascinating men.

There’s also a serious question to be raised in Greenberg’s treatment of Langley. The trope of tortured genius is worn almost through at this point, and there’s no attempt here to question, humanise or deepen it. Scott is so watchable in the role, as he is in everything, that it’s only in retrospect that the character’s proximity to Steve Martin’s Ruprecht character in Dirty Rotten Scoundrels becomes apparent. There’s a freakshow quality, and an unhelpful implication, in the entire character. It feels badly out of date and unqualified. It brings much fine writing perilously close to disrepute.

There are other, more prosaic, issues with The Dazzle too. For all of its bar’s bijoux décor (and it is well bijoux), Found111 so far feels like an extraordinarily long climb to quite an unremarkable theatre space. Ben Stones’ design here, a kind of cross-section of a cube, with a long stretch of junk heading upstage to nowhere, fails to capture the cramped confines of the real Collyer flat, where Langley’s body was able to lie dead and undiscovered for 12 days following the finding of Homer’s.

Director Simon Evans makes a much better fist of the direction; particularly in a superb stretch at the opening of Act 2 that allows Dawson a stretch of direct address (which survived an untimely intervention from a noted, oft-be-hatted senior critic on press night).

If The Dazzle has the air of event theatre, it’s largely the result of that superb double-star-billing, and it’s a draw that doesn’t disappoint. Scott has long established himself as one of the truly un-missable performers on the London stage, and the fact that he’s genuinely outshone on several occasions by Dawson here makes an uneven production of an uneven play close to a must-see.