Okay kiddo, so British Steel Corporation was a big company that used to make a lot of steel in the United Kingdom. Think of it like a real-life version of the toy factory in the North Pole that makes all the toys for Santa Claus.
In the old times, people used a lot of steel to make things like cars, buildings, bridges, and even airplanes. So British Steel Corporation had a really important job because they provided the steel that made all of those things possible.
The company was around for a long time, but it faced some really hard times. Imagine if Santa's toy factory suddenly ran out of toys to make and there were not enough kids to give them to, that's kind of like what happened to British Steel Corporation. People started using less and less steel, and then cheaper steel was being made in other countries, so British Steel Corporation was struggling to keep making profits.
Eventually, things got so bad that British Steel Corporation had to close down entirely. But don't worry, because there are still other companies out there that make steel, just like there are other toy factories that make toys. And who knows, maybe one day British Steel Corporation will come back to life and make steel again, just like Santa's toy factory always keeps on making toys!