When the summer riots spread to Hackney, the cry went up, “Don’t touch the Empire!” The theatre was seen as a place of good work and community value by the very people who were vandalising property and looting the shops outside.

This is one of many valuable nuggets in The Riots, a skilful verbatim documentary compiled by Gillian Slovo from spoken evidence; she made direct contact with rioters, police officers, community workers and local politicians, including Diane Abbott, Michael Gove, Simon Hughes and Iain Duncan Smith.

If there were a few more “Empires” in Tottenham, Wood Green and Brixton the trouble may have been averted, or at least contained: Slovo’s work, and the informative and detailed Tricycle programme, amounts, in effect, to the enquiry into the events of last August that the coalition government, astonishingly, refuses to authorise.

Is it theatre? Up to a point, though it’s not what you’d call “a show” any more than were the previous Tricycle enquiries into Stephen Lawrence, Hutton, the Nuremberg Trials, or Guantanamo (which Slovo compiled with Victoria Brittain). Instead, we have theatre as tribunal, a sort of carefully shaped and extended BBC discussion programme to satisfy the liberal breast-beating classes.

Nothing wrong with that: they’re the theatre audience, even at the right-on Trike. And Kent has assembled a fine cast to sift the evidence, anchored by Steve Toussaint’s gentle giant of a racial equality consultant, Stafford Scott. Diane Abbott (deliciously done by Dona Croll, who doubles wickedly as the colourful Kids Company guru, Camila Batmanghelidjh) diagnoses “a classic race riot.”

And of course it emerges that many of the kids live cramped and underprivileged lives with no leisure facilities or motivation. Michael Gove accuses “a vicious, lawless and immoral minority,” and that’s that. The show steers a sensible middle course, even humorously detailing the “free shopping” aspect of it, with looters testing out trainers, and criminal master-chefs cooking up in McDonald’s.

There’s a very sensible question asked: what difference is there between a kid stealing a television and an MP fiddling his expenses? The “exemplary” custodial sentences – including 18 months for the TV-snitcher – seem excessive, especially as the legal and political systems went nowhere in trying to understand the root of the trouble.

That root may be ineradicable, which is why the politicians keep mum. They’re running scared of what they know might happen in the current global mood of disaffection and uprising. The most terrifying aspect of it all was that the riots were triggered by the death of Mark Duggan in a police shoot-out; protest soon turned to wide-ranging anarchy.

The design by Polly Sullivan uses riot shields and animated maps, bursts of onstage fire and video footage to recreate the mayhem. Then the talking heads move in, with eloquent contributions from Cyril Nri as a Tottenham pastor, Tim Woodward as both the Metropolitan Police chief and Iain Duncan Smith, and Kingsley Ben-Adir as an analytical youth worker.

The Riots may not be great theatre, but it’s necessary theatre. And you’ll want to keep your programme to continue the discussion on the way home.