Pauline was a bankrobber - for Fringe show

Image caption A Machine To See With is produced by Blast Theory

I'm standing at a carousel in Edinburgh's Princes Street Gardens, scrutinising the crowds and feeling like a character in a cold war novel.

Any minute now, I'll receive a phone call from an unidentified man, telling me where I should go next in my attempt to rob one of the city's most high-profile banks.

Welcome to the world of Blast Theory and their new production A Machine To See With.

Anyone who plans to see this promenade, interactive show in its short Edinburgh run (until Sunday) should stop reading now.

The less you know about the production, the more you'll enjoy it.

First premiered at Robert Redford's Sundance Festival, its filmic atmosphere is no coincidence.

The story of an attempted bank heist is based on the Jean Luc Godard film Made in USA, which is in turn based on the The Jugger by Richard Stark.

The title "A machine to see with" comes from a line in the film but it could also refer to the mobile phone in your hand, which issues both the performance and the stage directions over the course of the next 50 minutes.

There are potential problems, of course.

Like your mother phoning in the middle of the show.

Or indeed patchy reception which means some of the more detailed descriptions are scrambled.

But I persevere, following the path to the public toilets behind the bandstand where I'm instructed to lock myself in and hide all my money in a safe place, on my person.

Previous work by this Brighton-based theatre company has seen theatregoers "kidnapped" during performances so I'm slightly apprehensive as I emerge for the next location (not least because I'm emerging suspiciously from a public toilet in a city park).

Listen attentively

I'm heading for the Grassmarket, looking for possible partners in crime, or indeed anyone else who's at the same show (participants are dispatched from the venue 15 minutes apart).

The problem is that everyone is on the phone.

Even narrowing it down to those who are not talking, but listening attentively, doesn't help.

Then, a breakthrough. I spot the director of the National Theatre of Wales scurrying down the Grassmarket.

We eye each other with embarrassment at the Grassmarket sign.

"You're at the same show as me," I say.

"I'm lost," he says.

"I'm having real problems following the directions."

A little local knowledge clearly helps.

We go our separate ways into the NCP car park - let's hope car park and toilet attendants across the city have been warned about strange characters hanging around.

I have to find and monitor a silver BMW which is parked on the third floor.

I can rarely find my own car in this car park so don't hold out much hope.

But after a bit of wandering, there it is.

Only a girl has just got in.

I'm told to watch from a distance so I hide behind a pillar (although my cover is blown by some tourists who stop to ask for directions for the exit).

Both girls get out and I call my contact back (it's all clearly recorded but it's amazing how important that disembodied voice becomes) and I'm told to get into the driver's seat and lock the doors.

In a few minutes, my accomplice will tap three times on the passenger window and I should let him in.

Police box

Meanwhile, the disembodied voice talks about corruption, the banks and the collapse of the global economy.

After 10 minutes, there's no knock and no suspicious people wandering around the car park.

My accomplice is lost. Or perhaps he got cold feet.

I use the keypad to reply that I want to take the option of going on my own.

I'm directed to a police box and then a clock and then the square outside the Clydesdale Bank.

I'm asked to consider all sorts of scenarios - would I hurt the security guard? Use a gun? Do I have an escape route planned?

Then I'm instructed to walk towards the entrance of the bank.

Just as I'm stepping forward, and wondering if the bank really has signed up for this sort of interactive theatre, the voice in my ear starts yelling "stop, stop, stop! Turn around and get out of there. As fast as you can."

Shame-faced, I head away towards a cafe on the square.

I'm wondering whether to grab a coffee and listen to the end of the show in comfort. Are they watching? Would they know?

I play safe and follow the instructions, arriving finally at a bus stop in the west end of the city.

I'm asked to observe the ordinary people around me, choose a person, imagine their life.

No-one bats an eyelid at me, slightly warm from an attempted heist and a lot of walking, and listening to the end of a performance only I know has happened.

A Machine to See With is at St George's West every 15 minutes from 1400 - 1900 until Sunday.