Orange uniforms, gloomy cells and sadistic guards might not sound like the ideal ingredients for a fun night out, but "Alcotraz" cocktail bar believes London's drinkers are ready for some time in the cooler.
"Back against the wall!" a guard barks to a group of thirty-somethings celebrating a birthday.
The guests comply, slipping into orange jumpsuits with numbers sewn on that will become their identity for the next two hours, during which they will be harassed by staff from Alcotraz, a pun on the name of the famous San Francisco prison.
"Hurry up, you're slow!" shouts the guard as the prisoners are shepherded inside the bar, which consists of a row of small and poorly lit metal-bar cells decorated with graffiti supposedly written by former prisoners.
The concept is the idea of 27-year-old entrepreneur Sam Shearman.
"Alcotraz is a unique combination of immersive theatre involving actors and also world-class mixology" -- the art of cocktail mixing -- he told AFP.
The bar is inspired by prisons from famous works of fiction, such as "Shawshank Redemption" and the Netflix series "Orange is the New Black". But Sherman stressed it was not intended to "make a mockery" of the penal system.
Detainees are always under the steely gaze of Alcotraz's brutal director, Carol-Ann Hooks-Johnson, in her long black dress and military boots.
"What am I saying, loser?" she shouts in her Southern drawl at one lag, who made the mistake of ignoring one of her commands.
Repeat offenders face the humiliation of having to kiss the shoes of their fellow prisoners, among other punishments.
However, guests are still willing to pay for the ordeal, even dreaming up their criminal past between drinks.
"It is really a bit intimidating, it does scare you a little bit but it's a great laugh," said David Morgan, 32, a finance worker.
"You need to experience this once in your life. It's something that you need to put on your bucket list."