There is nothing more annoying than a computer system that works beautifully, say, in a library, and then one goes in at nine thirty in the morning and you can't get books out because the power has gone off, and if we are sure to go on having a society with industrial disputes, we want a system that is not capable of being completely ruined by one small section of workers deciding not to work on a particular day, and so I think while we're putting them in, while we want to put them in in a way which that is compatible, we also need to think of having a kind of fail-safe system, particularly in the sort of more serious applications such as medicine and transport and so on, whereby we can't be held to ransom by very a small group of people, or indeed by just some technical fault, such as a power failure or something of this kind.