An Opinel No8 is illegal to carry on two counts, the blade is longer than 3" and it is a locking Knife, and despite having a good reason to carry it, there are however too many places you are not allowed to carry a knife at all, eg.Schools,etc, whenever you carry any knife whether its legal to do so or not, it will depend on where you are, what you are doing, and your attitude, and most of all the attitude of the person who has stopped you, unless you are doing something really stupid the chance of being searched and stopped is minimal, but my advice is, never carry an illegal knife unless it is absolutely necessary and you can back it up 100%, the Judiciary are against anyone carrying a knife and will prosecute whenever they can..........think of it as having a drink and then driving, its chancy, but if they think you are in the wrong, they will throw the book at you