mammoth wrote:

sometimes the laws are so ridiculous you have to ignore them. in reality, the worst that would happen is it's confiscated at the border.

That's not always the case here in the UK. Yes, confiscation is usually applied to many things that fall foul of the law. But (deemed illegal) weapons are regarded as a very different kettle of fish. Which presumably, is why the OP has made it clear he's not referring to anything other than the shipping of UK-legal knives.