Forget the physics. The greatest experiment in Michael Frayn's threehander is in the dramatic form itself.
It isn't merely Copenhagen's unlikely subject: the meeting in 1941 between Danish physicist Niels Bohr and his German protege, Werner Heisenberg.
Nor is it that it treats this encounter less as fact than as a series of speculations to be tested, as if the stage itself were a laboratory. It is also that Frayn dares to put arguments about quantum theory in the very place where most playwrights would field old-fashioned devices such as plot, action and characterisation.
That he does this while capturing a sense of the politics of the Holocaust and the arbitrary way in which we have escaped global catastrophe suggests Frayn is more eccentric genius than mad professor. Even so, it is an experiment that comes at a price.
At its best, as in the tremendous rallies between Tom Mannion's Bohr and Owen Oakeshott's Heisenberg in Tony Cownie's production, the play is a dazzling drama of ideas, headily matching concepts about splitting the atom with a debate about taking moral responsibility for one's actions. At its worst, in those moments when the actors seem dwarfed by designer Neil Murray's set of outsize control rods, it is a play in which the physicists tell each other what they must already know, while Sally Edwards, as Bohr's wife, chips in like a character from an arch sitcom.
Mannion and Oakeshott give assured performances, but the lack of action means you're sometimes more impressed that they have learned their lines than you are engaged with the big ideas.
