"London: poverty, homelessness, rising inequality, unemployment and industrial disputes..." It's all too easy to see why the Finborough and Fat Git Theatre felt that Howard Brenton's 1973 play Magnificence was ripe for revival.

The band of would-be revolutionaries Brenton sets up in a run-down squat may talk more like characters in a play or political mouthpieces than real people, but there is no mistaking their fury and frustration speaking to us across the 43 years since the Royal Court premiered this occasionally clunky but still potent piece.

In Josh Roche's pacy, mostly engaging staging, the younger actors sometimes struggle to make Brenton's abrasive, somewhat overwritten dialogue sound like genuine speech, and certainly in the first half it never feels like there is quite enough at stake. The worthiness is welcomely leavened by an Orton-esque middle scene between an inept constable (Tim Faulkner who impressively doubles as a slimy Tory politician) and a thuggish former policeman now dead set on evicting the squatters by any means necessary (excellent, twitchy Chris Porter).

The second act is undeniably stronger, starting as it does with a brilliantly witty scene between an ancient Tory grandee on his very last legs (Hayward B Morse delivering a masterclass in fine acting, both deeply poignant and hysterically funny: "these may be my last moments, I don't want to spend them bitching") and the elite protégée he is not about to let off the hook (Faulkner again, bearing an uncanny resemblance to Michael Grade). Morse's final, corrosive accusation - "you are a modern, peculiarly English kind of fascist. I think there's a very real and terrible danger that YOU may inherit the earth" - feels chillingly prescient, and this whole section is pretty much perfect, achieving the ideal balance between disturbing and entertaining.

Elsewhere the script feels very much like a "young" play - Brenton went on to write infinitely more accomplished political dramas - and one that tends to lecture rather than theatrically demonstrate what it is trying to say. Joel Gillman, terrific as disillusioned and desperate Jed, does however go a long way towards convincing us that there is more to his character than what is actually in the text. I have no doubt we'll be seeing a lot more of him in the future.

Really worth seeing, if not entirely satisfying.

Magnificence runs at the Finborough Theatre until 19 November.