The play's transfer now to the West End, with the same consummate cast (David Burke, Sara Kestelman, and Matthew Marsh) confirms the justice of all this praise. One of the play's great virtues is its absolute purity of focus; it trains its lens on three characters who are still arguing, in limbo beyond the grave, about what really transpired when the German nuclear physicist Werner Heisenberg made a mysterious, fateful and inconclusive visit to his former teacher and mentor, Niels Bohr, in Nazi-occupied Copenhagen in 1941. Was his mission to warn Bohr of the German atomic bomb programme or to try to recruit him for it?
The play's austere concentration was heightened in the Cottesloe by placing the action on a bare circular set with part of the audience sitting on steeply raked seats at the back, like jurors. The Duchess Theatre has such an intimate lecture-room atmosphere that similar conditions can be created with amazing ease.
Seeing Copenhagen again, I was struck by the powerful way it engages the feelings as well as the intellect, a fact perhaps under-emphasised the first time round. The play is much more than a cerebral thriller about shifting interpretations and the painful ironies that proliferate from the conjunction of pure science and impure Realpolitik.
Delicately applying Heisenberg's Uncertainty Principle, the drama develops into a profound and haunting meditation on the mysteries of human motivation. It is also a sad love story of sorts, the older scientist seeking, and then feeling betrayed by, a substitute son.
Michael Blakemore's superb production is beautifully attentive to the play's recurring rhythms, as this trio endlessly re-enacts that momentous 1941 encounter. A demanding and richly rewarding evening.