The National Theatre's award-winning production of Joe Penhall's Blue Orange will open at the West End's Duchess Theatre with its original cast of Chiwetel Ejiofor, Andrew Lincoln and Bill Nighy. From 30 April 2001, the drama replaces the National's 1998 hit, Michael Frayn's Copenhagen, which has been playing at the theatre since February 1999.

The play concerns medical ethics and racism in a London mental hospital. Nighy and Lincoln play two doctors in disagreement over the correct treatment for Ejiofor's black schizophrenic patient who claims to be the son of exiled African dictator, Idi Amin.

Blue Orange had its world premiere in April at the NT Cottesloe, where it enjoyed a sell-out run to 23 August 2000. It has already scooped two major prizes - Best New Play and Outstanding Newcomer - at last month's Evening Standard Theatre Awards, the first of London's season of awards ceremonies.

Penhall's previous work includes Some Voices, which won the 1995 John Whiting Award, Pale Horse, winner of the 1995 Thames Television Writer's Award (both for the Royal Court), Love and Understanding (Bush), and The Bullet (Donmar Warehouse). Blue Orange is directed by Notting Hill film director Roger Michell and designed by William Dudley with lighting by Rick Fisher.

Copenhagen, which ran first at the NT's Cottesloe and then Lyttelton theatres before moving to the Duchess, tackles the mysterious 1941 meeting in Copenhagen between the German physicist Werner Heisenberg and his Danish counterpart, Niels Bohr. They were old friends and their work together had opened the way into the atom, but now they were on opposite sides of a world war and the meeting would end in disaster.

The drama received both the 1998 Evening Standard and Critics Circle Awards for Best New Play, while the Broadway transfer production also won Best Play and Best Director honours at last year's Tony Awards. Copenhagen currently features David Baron, Corinna Marlowe and William Brand. It is directed by Michael Blakemore, with design by Peter J Davison and lighting by Mark Henderson. Michael Frayn's many other plays include Alarms and Excursions, Benefactors and Noises Off, which is currently being revived at the NT Lyttelton.