The Privy Council of England is a group of important people that help the King or Queen make really important decisions. It's like having a group of grown-up advisors to help you make decisions in your own life.
The Privy Council has been around for a really long time- even before you were born- and it's actually one of the oldest parts of the British government! The group is made up of important people like the Prime Minister and other government officials, as well as a few people who are chosen by the King or Queen to be part of it.
The whole idea behind the Privy Council is to make sure that the person who is in charge of the country (the King or Queen) has a group of really trustworthy people to help them make very important decisions. For example, if there is a big problem in the country, such as a war or a natural disaster, the Privy Council can help the King or Queen figure out what to do about it.
So, in summary, the Privy Council of England is a group of important people who help the King or Queen make really important decisions, and they have been been around for a really long time.