Wiretapper (Secret Location)

David Rosenberg, Andrew Rutland and the Ringham brothers' open air show lets participants loose in locations around central London at sunset. Audiences are free to wander round and track down a story communicated to you by headphones and by Wiretapper, the audio app you download to participate in the show.

At the secret location, we are told to put headphones in and stand still, instructed to blend in with the surroundings. In busy central London, this is not a hard task. As you look around trying to decipher who may be part of the show and who is a meager spectator, the paranoia kicks in. "We can see you and we are watching your every move," a voice purrs into your ear.

Wiretapper focuses on precisely that point; the surveillance state and the fact that constant CCTV recordings track your every move with no public space safe from someone watching.

Listening into instructions and conversations which direct your movement, you're offered a glimpse into the world of a man called Michael, he knows they're watching and he can help you to be inconspicuous, he is the only one you can trust. Right?

The performance takes a strange turn and to give further details would be to give away spoilers but as a series of events unfold and you are led around the city, you can't help to look at it with fresh eyes. Is that man with a briefcase really waiting for a bus? Who is actually on the tour and who is just walking past? A cab pulls up at one point and a man jumps out, running down the stairs and off into the distance. Apparently nothing to do with the show but it makes you feel nervy, why is he running and should I be?

The soundscape cannot be faulted, at numerous points I found myself turning around to try and work out if someone was behind me, or looking up to try and see a helicopter in the sky which wasn't there. Odd moments have a nice poignancy as well; a red balloon lost by a child floats high over the city and into the sunset, free, no longer trapped amongst the busy crowds and cameras.

But for all of this, I couldn't shake the feeling that I was waiting for something to happen that never quite did. A grander action, a more profound statement, more characters to unsettle us. As an experience it's strangely interesting, a disquieting evening which shows how technology has a hold over us and even over our free will – as we gaze at a big sign declaring 'CCTV in operation' and 'don't feed the pigeons', we are given advice on how to discreetly rebel – put breadcrumbs down your trousers, they won't be able to see the trail you leave for the birds.

Moments like this are nice and 'listening in' to conversations and inner thoughts makes you feel like you're uncovering a secret society you always wanted to be in but Wiretapper doesn't quite tap into the full extent of the terrifying hold technology has over us. They will always be watching.

Wiretapper runs at secret London locations (Zone 1) throughout the summer. Head to their website for more tickets or more information.