Under the menacing eye of guards, viewers sit in silence as their 1950s bus rumbles through London. Suddenly, a prison looms out of the darkness.

Welcome to Secret Cinema, where the film is not just on the screen - viewers can wander up to the characters, brought to life by actors in a setting that seems to have been plucked straight out of the movie.

Guests arrive armed with nothing more than a string of cryptic e-mails detailing where to go and how to dress. They don't even know what film they are going to see, despite having paid 43.50 pounds ($70) each for a ticket.