Well, that's hilarious. Many UK houses to get their hot water from a tank heated by the same boiler as the central heating system, with both turned on and off by a central timer plus individual thermostats. It sounds like the Nest can't handle that, meaning you still need a separate non-Nest timer for the hot water as well with its own user interface.[1]

[1] See the comments on http://www.trustedreviews.com/news/nest-thermostat-officiall... - I thought it was odd the Nest PR stuff didn't mention hot water anywhere.