I believe the OP wasn´t referring to self-defence situations.
That said, I agree with Phil, take nothing and buy a cheap-ish multi-tool with non-locking blades locally and keep the receipt. If you then get stopped by the police, you can explain that
a) you bought it in the UK, so as far as you know, it should be legal and
b) you´re carrying it on your person because you bought it so recently, you slipped it in your coat pocket coming out of the shop and kinda forgot about it, heck, you still got the receipt with it too
I can´t see how they could possibly charge you with anything under those circumstances.