The target of these laws is not kitchen knives. Pocketknives (manual blade, less than 3") of most kinds are legal.[1, see exceptions] Bans of this kind are fairly common (for instance, in California, there is a ban on concealed carry of fixed-blade knives; in Los Angeles, the ban extends to openly carrying a "knife or dagger" defined as "any knife having a blade of three inches or more in length".[2] These laws strike me as very reasonable.

[1]https://www.gov.uk/buying-carrying-knives [2]https://www.losangelescriminallawyers.com/los-angeles-knife-...