The Permanent Under-Secretary of State for Foreign Affairs is a very important person in the government of the United Kingdom. Imagine that the government is like a big school, and the Permanent Under-Secretary is like the head teacher of that school, but for foreign affairs. Their job is to help the UK government work with other countries, like America or Germany or China.
This person is responsible for making sure that all the people who work in the UK's foreign affairs department are doing their jobs properly and that everything is running smoothly. They also work with other countries to make sure that everyone is getting along and working together to make the world a better place.
The Permanent Under-Secretary is very smart and has a lot of experience in foreign affairs. They know a lot of important people from other countries and are good at making friends and working out deals that help the UK. They are very important because they help to keep the UK safe and to make sure that the country is respected around the world.