On the day that 500,000 people were marching against the government’s cuts in London, and the culture secretary was twittering away at that jolly knees-up and bastion of the establishment The Boat Race, it felt particularly urgent and timely to be taking a seat for Belt Up Theatre’s contribution to the York Theatre Royal’s Takeover Festival. Rarely does a trip to the theatre make you feel that you are part of something much, much bigger: a social movement and common feeling, an ideology that transcends history, and a repeated and seemingly inescapable political cycle. Yet with James Wilkes’s re-working of John Gay’s 1728 satire The Beggar’s Opera, Belt Up doesn’t only offer a frantically fun night of anarchic musical theatre, but also an impassioned attack on the politics of today, yesterday and yesteryear that seeks to unite everyone in an understanding of what it really means to all be in this together.

In its quintessentially metatheatrical way, Belt Up immediately introduces us to a troop of ’80s leftie luvvies putting on a delightfully shambolic version of Gay’s piece, which in turn focuses our attention on the legacy of the Thatcher era to the politics of today. You feel in safe hands as Dominic J Allen takes the mic to narrate their theatricals, and he switches deftly into a brilliant wheeling and dealing Mr Peachum. His quickfire justification for exploitation and corruption, and constant insults at Joe Hufton’s affably dim Filch, make for a blistering opening to a play that doesn’t once pause for breath. The Beggar’s Opera certainly pins its colours to the mast from the outset, with Peachum and Filch’s outrageous rap on the Daily Mail, Mrs Peachum’s fabulously un-PC racist ditty, and the sort of imaginative expletives that would make Malcolm Tucker blush. In fact, so much is crammed into the first act that by the interval your mind is already full to bursting point, yet it is mercifully unnecessary to pick up every in-joke, topical reference or criticism of Tory politics to get the outrageous gist of where The Beggar’s Opera is going.

Few political figures evoke such wild loathing or hero-worship as Maggie Thatcher. As the cast hold their middle fingers aloft in salute, it would be all too easy for The Beggar’s Opera to descend into posturing or provocation for its own sake, yet remarkably, the vitriol never quite feels gratuitous. Laura Horton is tasked with sexing up the Iron Lady into brothel keeper Madam Snatcher, obscene in her stockings and wig and guilty of creating toe-curling mental images of incest with her own Tory Boys Gideon and David. With most of the political figures lampooned and caricatured into absurdity, there is a nice contrast from Serena Manteghi’s fiery Polly Peachum and James Wilkes as the lothario Macheath, who maintain the heart of an otherwise bonkers piece. Interesting too is the character of Mr Lockit , who is reviled for breaking promises and abandoning principles in a desperate attempt to cling onto power (sound familiar?). While they go to pains to see his hypocrisy and idiocy hammered home, Lockit is nonetheless played quite sympathetically by Marcus Emerton, as a bit of a fool bullied and corrupted by Peachum.

The music by Alexander Wright and Dan Wood remains true to Gay’s intention, with a great mix of rousing singalongs and tongue-in-cheek mockery of the genre. The send-up of the start of each song gets funnier and funnier as the pretence is maintained, with the result that Mr Lockit’s unwilling maraca shaking, or Macheath’s continually frustrated face as he tries to get into Polly Peachum’s knickers, completely upstage either of the two women singing their hearts out. Belt Up uses live music evocatively in much of its work, yet the only thing that even slightly betrays the fact that this marks its first full-scale musical is an occasional tendency amongst some of the cast to drop and garble words while singing, meaning that nuances in plot or character are sometimes lost.

Arguably the ‘worst-kept secret choir’ manage to deliver a blissful surprise with musicians and vocalists emerging when you least expect it from amongst the audience. With voices washing over you from all sides, the choir create that uplifting feeling of inclusiveness you come to expect from a Belt Up show. However, their haphazard outfits niggle somewhat after they join the company on stage and their giggling is downright distracting. With the actors trussed up in all manner of hideous ’80s regalia, the sudden influx of some vaguely retro and other completely normal outfits confuses the stage picture. The play doesn’t need to include performers from the present day to get its message of contemporary relevance across – the biting satire manages that fine on its own – and so for a company so masterful at creating visual spectacles and turning large casts into a crazy array of characters, it feels as though it missed a trick here.

Which in the grand scheme of things is a pretty minor criticism for a show that is a riot to be a part of from beginning to end. Belt Up has you squirming in your seat, smiling wryly at the frequently throwaway but bloody clever one-liners, and aching at the injustice of firing a volunteer librarian. Brecht argued that while the purpose and justification of theatre is pure entertainment, the nature of what entertains us must fit in the scientific age, where the acquisition of knowledge replaces catharsis. The Beggar’s Opera captures this perfectly, as although it is thoroughly entertaining it also succeeds in making you think about how we ended up in this political mess, and what it is going to take to get us out; what it means to take a stand against a government whose policies you don’t agree with; and what society is and should be, and the individual’s place in that.

After the sleaze and bile of the show, the ending is euphoric, democratising and hopeful – a feeling compounded when you reflect on what Belt Up has actually achieved with The Beggar’s Opera. As anger mounts it’s all too easy to lose sight of the fact that we live in a society where leading politicians have sent their best regards to the makers of a play that ridicules everything about their corrupt, privileged and hypocritical existence. In a world where elsewhere theatre-makers are silenced and persecuted for daring to even practise their art, the fact that Belt Up have created such a stunning, accomplished and vital piece of theatre for the here and now is something to be celebrated.

Belt Up Theatre‘s The Beggar’s Opera ran as part of the York Theatre Royal Takeover Festival 2011 from 24 – 26 March.