In order to increase access to the National Theatre for those who are blind or visually impaired, the Access Department employs freelance Audio Describers for each production to describe what is happening onstage during live performances.

Watch a set change in the Lyttelton theatre

The Cottesloe Theatre is the smallest and most flexible of the National's three theatres. The theatre can accommodate a number of different seating configurations and is most often used to present newer and more experimental theatre.

Nicholas Hytner gives a tour from the southbank of the river Thames into the National Theatre and through each of the different theatre spaces in the building.

As Director of the National Theatre, Nick Hytner is responsible for all aspects of the building. His prime focus is artistic; the work going on the various stages needs to be programmed and overseen. However, he also has to make sure that all the logistical and administrative areas that are vital to an organisation like the National are running smoothly.

The drum revolve of the Olivier theatre allows quick and dramatic scene changes. Experience a typical scene change using the drum revolve from perspectives in the auditorium, below the stage and on the set itself.

The Lyttleton is a traditional proscenium arch theatre.

A theatre's flying system is a vital way of effecting quick scene changes, as the fly tower can store large pieces of set and then lower them down on to the stage very quickly. Traditional flying systems (like the one in the Lyttelton) use a series of bars, but the individually controllable point hoists in the Olivier give Automation Manager Jamie Taylor considerably more options to play with.

The Olivier Theatre is modelled on the ancient Greek amphitheatre at Epidauros, and has a special power as a forum for large-scale, public plays.

Many theatres make use of simple revolves; they're like giant turntables which sit on top of the stage and enable sets and actors to rotate. But the giant Drum Revolve in the National's Olivier Theatre dwarfs them all; rather than just a flat revolve, it is five storeys high, containing several elevators and enabling exciting effects like towers or boats rising out of the stage or objects suddenly disappearing from view.

To mark his 80th birthday, the director Peter Hall discusses his career and his latest production, Twelfth Night, with Nicholas Hytner.