This video from Britain says about itself:
11 July 2013
Original and stunning high definition slow motion footage of animals and their actions. Brought to you by our very own team members; butterfly admirer Nic and camera geek Simon.
From Wildlife Extra:
It is only the small tortoiseshell and peacock butterfly that regularly overwinter inside houses. They come in during late summer or early autumn, when it is still warm outside and our houses appear to provide suitably cool, sheltered, dry conditions. However, come Christmas, when the central heating is cranked up, these butterflies may be awoken prematurely by high indoor temperatures. This presents a major problem for the butterfly as the outside weather conditions may be very hostile and there is little nectar available in gardens.
It is also a problem for the concerned householder. How best to help these poor confused butterflies unwittingly tricked into thinking spring has come early? The best solution is to re-house the butterfly in a suitable location. Catch it carefully, place it in a cardboard box or similar and leave it in a cool place for half an hour or so to see if it will calm down. Once calmed, you might be able to gently encourage the now sleepy butterfly out on to the wall or ceiling of an unheated building such as a shed, porch, garage or outhouse. Just remember that the butterfly will need to be able to escape when it awakens in spring.
If you have no suitable hibernation place, then it would be best to keep the butterfly as cool as possible, to minimise activity, and then to release it outside during a spell of nice weather.