I carry a small folding knife, am I breaking the law? No. You can carry a knife in public if it has a folding blade that is 3 inches (7.62cm) or less in length. However if any knife is used to threaten or intimidate it is considered an offensive weapon.

In the UK, the law regarding knives is very specific and revolves around the concept of "folding pocket knives." You can legally carry a knife in public without a "good reason" only if it is a non-locking folding knife with a cutting edge of less than 3 inches (7.62 cm). This is often referred to as a "UK-friendly" or "legal carry" knife. Crucially, if the knife has a mechanism that locks the blade into place when open, it is no longer considered a "folding pocket knife" under Section 139 of the Criminal Justice Act, and carrying it in public without a valid reason (such as for work or religious purposes like the Sikh Kirpan) can lead to arrest and prosecution. Even for a legal 3-inch non-locking knife, you can still face trouble if you carry it in "high-risk" areas like schools, nightclubs, or football stadiums, where private security or local bylaws may prohibit all bladed articles. The golden rule in the UK is that "intent" matters; using even a legal knife in a threatening manner is a serious criminal offense, regardless of the blade's length or mechanism.