Which for the majority of the UK means unpurchasable. With high rents in many places it's getting extremely difficult for a lot of people to save enough even for a deposit on a house, let alone buy it outright.

Oddly I think refusing to mortgage homes on flood plains is actually a good call by the banks. The local councils are just building in whatever idiotic places they like, stripping hills of the foliage which absorbs water to put houses there, then putting even more houses below where all the water now has to flow.