“It is illegal to carry a knife in public without good reason – unless it’s a knife with a folding blade 3 inches long (7.62cm) or less.” It seems like it is therefore legal to carry a larger knife or even a fixed blade as long as it’s for “good reason” but I wouldn’t push my luck.
All locking knives are banned, including those in multitools such as the Victorinox Cavalier. There’s also a host of banned knives and weapons in the books, such as butterfly knives, flick knives, gravity knives, disguised knives, zombie knives (even those that fall under the regular regulations!), and more.