It all starts with a knock on a door and a meeting with a confused old man in a darkened room.

And then the audience is thrown into dreamthinkspeak’s world where anything can happen.

Before I Sleep is a truly interactive, immersive experience, mixing theatre and art installation, which takes a long time to leave the memory.

A big part of its success is the surprises that one meets along the way, in the new worlds created by the Brighton-based theatre company.

Although inspired by Anton Chekhov’s The Cherry Orchard, prior knowledge of the original play isn’t necessary – although those who do know it may get more out of the tableaux scattered around the building, in particular in its opening sections.

But this new piece also draws heavily on its previously abandoned setting, with the building acting as a character in its own right. A recurring theme is regeneration, the decay and eventual destruction of an old world ready for the arrival of a new one – easy for anyone to relate to, particularly if they know the history of London Road and the many empty buildings scattered around Brighton.

The piece creates its own narrative along the way, with strange references, such as the snorkelling gear that can be viewed in the window, making sense the further one goes.

The audience, which goes through the space in timed small groups, is able to make its own way, with only occasional nudges to the right path by some of the cast.

And it pays to take your time, to investigate the detail of some of the amazing installations, and drink in the amount of work that has gone into transforming this building.

Those fearful of audience participation don’t have anything to worry about – the piece has been designed so visitors need not say a word to the characters along the way without it feeling strange.

It is an unforgettable, amazing experience, and a worthy Angel winner that will leave you wanting to go back for more.

*Call 01273 709709