I got one like that on my keychain too and while the personal at the airport measured the blade size, it was fine to take along for an international flight with

I got one like that on my keychain too and while the personal at the airport measured the blade size, it was fine to take along for an international flight within the EU. I'm neither from the UK nor a lawyer through, and airport personal aren't the police, still hard to imagine that they'd ignore that if it was illegal.