The home secretary has a lot of control over laws, using a thing in the British law system called a "statutory instrument". That is, a law passed by parliament

The home secretary has a lot of control over laws, using a thing in the British law system called a "statutory instrument". That is, a law passed by parliament that says that a named person (usually the home secretary) has the power to switch on and off a very specific law as they see fit. There's a surprising number of laws that are controlled that way. It's in some ways a neat invention, in that it allows laws to be fine-tuned without having to go through a whole parliamentary hearing. For instance, if a law against people being obnoxious in some particular way becomes irrelevant because people have stopped being obnoxious in that particular way, then the home secretary can just switch it off. But it has to be set up by parliament in this way in advance.