 A terrorist group has planted a small nuclear device with a timing mechanism in London and it is about to go off. If it does it will kill thousands and make a large part of the city uninhabitable for decades. One of the terrorists has been captured by the police, and if he can be made to disclose the location of the device then the police can probably disarm it and thereby save the lives of thousands. The police know the terrorist in question. They know he has orchestrated terrorist attacks, albeit non-nuclear ones, in the past. Moreover, on the basis of intercepted mobile phone calls and e-mails the police know that this attack is under way in some location in London and that he is the leader of the group. Unfortunately, the terrorist is refusing to talk and time is slipping away. However, the police know that there is a reasonable chance that he will talk, if tortured. Moreover, all their other sources of information have dried up. Furthermore, there is no other way to avoid catastrophe; evacuation of the city, for example, cannot be undertaken in the limited time available. Torture is not normally used by the police, and indeed it is unlawful to use it.