Adventure One (Sprint Festival)

St Paul’s Cathedral dominates its surroundings. It looms up over the City of London and Paternoster Square in particular, home of the London Stock Exchange, the nerve centre of Britain’s financial sector. It’s a surprisingly inauspicious building: no columns, no grandeur, just brick and glass. There’s a Pret on the bottom floor. It seems to be hiding in plain sight.

That’s exactly what interactive theatre-makers Coney ask us to do in Adventure One, a covert mission through the City of London and its privately-owned public spaces. You could be any idle tourist, listening to music as you see the sights. Instead, your headphones are imparting the secrets of the system: its coded Masonic messages carved into walls; its unmarked buildings with their security guards; its warp-speed algorithms that, in 2010, triggered a flash crash, as the markets suffered a palpitation, dropping 10% in a day, and narrowly missing a meltdown.

Our target, Mr X, is the sort of city-worker responsible for such mechanisms; not a flash Cityboy, but a former scientist with a head for figures. The soundtrack we’ve downloaded is full of information on him and, following instructions via text messages and recorded phone calls, we trace his daily routine: coffee in Pret, fag by a fire escape, prayer in St Dunstans chapel. Who is this man? What power does he have? How does he feel?

There’s always a thrill to an experience like this: in public, but undercover, and never quite sure what you might be asked to do next. When a phone booth rings just for you, you can’t help but feel like George Smiley. You become privy to another side of your surroundings, noticing that which is easily overlooked. Those swish offices above One New Change, for instance, that we, distracted by all the shops and bars at street level, tend not to notice. You get all the best views and all the secret doors – places Joe Public may or may not be meant to go. Who owns these spaces? And who’s holding those people to account?

It’s a smart piece, one that prods at your assumptions in all manner of ways, then picks apart the ramifications afterwards. Not only does it get you into Mr X’s head – a worker bee, remember, wrangling with his own conscience – it lets you feel both powerful and passive. Playing means pushing the usual modes of public behaviour, yes, but at the same time you’re just following orders. As the piece pushes you onwards, closer and closer to Mr X himself, the question is whether you ever stop to question your actions. Who’s calling the shots – and why?

Adventure One runs as part of the Camden People’s Theatre Sprint Festival on weekends in March. Details here.