“This isn’t a play. It’s a story” declares Anthony Calf’s Author to launch David Hare’s bid to get to grips with how the stuff of the world economic meltdown happened. If anything, Hare tells two stories, both absorbing and indeed amounting less to a play (it’s fittingly subtitled “a dramatist seeks to understand the financial crisis”), more to reportage. There’s the story of the crisis itself, and the story of his efforts to understand it as he engages with multi-national financiers, economists, academics, journalists – and even the man from the Citizens’ Advice Bureau, all real people, most well-known names.

In just under two hours they trace the complexities of this fall from grace of banks and bankers in ways that the self-confessed financially ignorant Author, who raises eyebrows when he admits to keeping his money in the Post Office, can understand. Which, of course, means that anyone in the audience not in the world of finance (and I suspect plenty at press night were taking time out from wheeling and dealing) ought to be instructed and shocked by turns as they make the journey to ‘enlightenment’ with the Author.

Thanks to director Angus Jackson’s strategic marshalling of his superb cast of 20, the journey is almost physically invigorating as well as intellectually. These men and women in monochrome suits march purposefully across the stage, at first all together to converge on the Author and then severally to engage with him one at a time in his quest .

It’s telling that they never interact with one another, merely swiftly and smoothly introducing the next player on the financial stage, an effective Brechtian device that keeps energy levels high. For these often arrogant and greedy money men (the three women are journalists and a researcher) are isolated by choice as much as circumstance, failing to connect with other people and ultimately with reality because of the single-mindedness that has become blinkered obsession with power and ‘the deal’.

The only colour comes from the witty digital surtitles and images on Bob Crowley’s bare set, which raises the biggest laugh of the evening (and this evening elicits plenty of knowing laughs) with an homage to the famous Andy Warhol Marilyn triptych featuring Fred Goodwin’s face.

Hare’s version of the story begins with the Black Scholes Equation for managing risk that too many traders thought was the Holy Grail and ends with the sobering thought that the economic future of the world is down to China. If anyone comes out of The Power of Yes well, it is at one end of the scale the financier and philanthropist George Soros (a beautifully studied portrayal from Bruce Myers) and at the other the young Sarajevan researcher Masa Serdavic, the Author’s guide and amanuensis (a simple and ultimately affecting performance by Jemima Rooper), who came to this country and to the world of finance when her own world fell apart.