The Power Of Yes, NT: Lyttelton, London

Subtitled "a dramatist seeks to understand the financial crisis", David Hare's hotly anticipated new piece is not so much a play proper as an edited dramatisation of the research process that could have led to one. Portrayed by Anthony Calf, the author-figure (who is a version of Hare) takes to the stage and scribbles endlessly in a notebook, while quizzing a recurring crew of financiers, politicians and journalists. But you feel that he must have been trapped for the past year in a bunker, such is the surprise he evinces when these men in suits (who include Adair Turner, the chairman of the Financial Services Authority and George Soros, a US banker) march forward and bark at him what we largely already know.

Howard Davies, the first chairman of the FSA, keeps dragging in a blackboard on which he's chalked the acronym S-L-U-M-P (for sub-prime, liquidity, unravelling, meltdown, pumping). This is supposed to gesture towards a quasi-Shakespearean five-act structure, but it merely emphasises the stolid, spelt-out-to-a-fault manner of the way the piece tells a momentous story that embraces the four days in September 2008 when capitalism came to a grinding halt.

Instead of the gripping play he might have written, Hare gives us a sort of "Everything You Wanted to Know About the Credit Crunch But Were Afraid to Ask". It's honourable, lucid, tenacious, but also a little dull. You want to have "securitisation" explained? Banker David Marsh has a good image for what happens when the originator and holder of a loan get separated. It's like pain moving round in disguise: "You stub your toe but it's your elbow which hurts". What we see, though, is the weedy spectacle of businessmen swapping pages from their portfolios.

Even as journalism, the piece lacks dialectical edge. Hare's central contention is that, to ward off legislation, bankers have a vested interest in denying that this recession (because of the collapse of the system in 2008) is radically different in kind to previous slumps. But the financiers to whom Hare talks are, by and large, rueful reformed characters who eloquently agree. His case would be toughened if he had to slug it out with the kind of unreconstructed swinging-dick Darwinian who might argue that the financial innovations that were criminal in one era have a habit of passing into respectability in the next.

To 10 January (020 7452 3000)