Television closedown routines in the United Kingdom are what happens when television channels finish broadcasting for the day and go to sleep. Just like how you have a bedtime routine before going to sleep, TV channels have their own routine too.
At the end of the day, when it's time to close down, the television channel plays a special little song called the national anthem. This song is like a lullaby to say goodnight to all the viewers. It's a way of showing respect and saying thank you to all the people who watched the TV channel.
After the national anthem, there is something called a test card. Test cards are like pictures that the TV channel shows when there are no more shows or programs to watch. They have colorful pictures and patterns that help the TV channel check if everything is working properly. It's a bit like when you draw on a piece of paper to see if your pen is working.
While the test card is on display, the TV channel might also show a clock. This is just like the clock you have in your bedroom that tells you the time. But instead of showing just numbers, this clock sometimes has pictures too. It helps people see how much time has passed and how long it will be until the TV channel starts again.
When it's time for the TV channel to go to sleep, they turn off the test card and the clock. The TV screen becomes completely black, like when you switch off the lights before going to bed. This means the TV channel is resting until morning when it wakes up and starts broadcasting programs again.
So, just like how you have a special bedtime routine before going to sleep, TV channels in the United Kingdom have their own closing routine. They play the national anthem, show colorful pictures and patterns, and then turn off the TV until the next day. It's a way of saying goodnight to all the viewers and getting ready for a brand new day of shows and programs.