Dual control? This is not a play to go to for a relaxing evening’s light entertainment, but it is stimulating and challenging. Chris & Priscilla Seidler, Streatham, London, SW16 Scene from the play | photo: variety.com THE HARD PROBLEM By Tom Stoppard The Dorfman Theatre (at the National Theatre) Running until 27 May subscribe now Join today to gain access to the rest of this article and many others. more info login If you are already a subscriber, log in to continue. log in access code If you have an access code, enter it here: Go free trial Get free access for 14 days: Sign up Click here to find out how we take care of your personal data.