guvnorThat's the UK youre thinking of.
Depends if this opens with one hand and/or can be flicked open. Also, customs officer's discretion, depending how much momentum they can impart to the blade.
DoozyIt is perfectly legal in Aus.
As long as you have a reasonable use to carry it. Eg sporting or recreational purpose or as part of your employment........if you take it down to the pub or something you'll might find that's a nono.
Flippers and knives that open with inertia are legal to own and use as above but are currently regarded as restricted weapons so you need special permission to import.
As I understand it there are changes afoot that will make owning modern folders fairer as long as they are used for a legal persuit well see...