Do you live in a protected building? Is it listed, or in a protected area – a national park, area of outstanding natural beauty or a conservation area? If it’s listed as grade 2 star or above, you’re unlikely to be able to install panels unless they’re completely invisible from public view. Contact your local planning authority see if it’s OK. (Just our opinion, but buildings have always evolved to suit contemporary conditions or new inventions, but now buildings have to be preserved in aspic forever, and apparently environmental sustainability is not as important as picture postcard / chocolate box prettiness).
If you live in a ‘normal’ house in a ‘normal’ street, solar panels are part of ‘permitted development’, i.e. you don’t need planning permission. But there are caveats. See the Planning Portal website for more information about permitted development rights and solar panels.