Do not carry a Leatherman Wave in UK where anyone is going to see it. In fact, don't carry any knife in the UK where anyone can see it.

If they don't know it's there, then it doesn't exist.

If you have to get searched or go through a detector, you will lose your knife if they find it. You may also be incarcerated, or otherwise hassled.

That is a gen purp rule of thumb. There will be exceptions. I wouldn't want to bet my Wave on knowing when and where.