The Shaftesbury Theatre is offering a new device to theatre goers, called Airscript. It enables you to read live captions of a performance in eight different languages.
The developers, Cambridge Consultants, hope the handsets will attract more tourists into the theatre.
The captions, received over wifi, scroll throughout live performances, you pay £6 to hire the device during a performance.
I think you should get a refund if you spot any mistakes though.