Sad to see the thread being turned political, but in the cold light of day rivers do tend to flood by increasing the height of the banks its moving the problem on somewhere down stream.
If you either are a believer or not in global warming with a wetter climate this is going to become more common event.
the existing homes will have to be flood proofed as much as possible, hard flooring concrete wall coverings etc but land is precious or this tiny island and building more homes on natural flood plains isn’t going yo help.
immigration isnt helping matters, building firms can throw up new homes on said flood plains, walk away with the cash and leave it too EA, councils and insurers to sort out
Rant over
Or perhaps the house building firms may have to also invest in the local infrastructure in order to get planning bit more of a rant