Clear Channel UK is a company that helps people advertise things on big signs and screens that lots of people can see. It's like when you see a really big billboard with a picture and some words on it while you're driving in a car. Clear Channel UK helps put those billboards and signs in places where lots of people can see them, like on the side of a busy road or in a big city. They also have screens in places like shopping centers, train stations, and airports where they show things like advertisements, news updates, or even the time and weather. So basically, Clear Channel UK helps people get their messages out there to lots of people in different places.