case varies. could be complicated and could be easy. In general, you need to pass the passport control in China and the UK. They will check your visa and ask you questions, e.g., why you come to the UK, etc. You need to show you have accommodation, funds and the English ability to answer questions. In case of changes, e.g., due to bad weather, follow the instructions provided by the airline. In case of unclear, ask staff in uniform at the airport.
In general, you need to pass the passport control in China and the UK. They will check your visa and ask you questions, e.g., why you come to the UK, etc.
You need to show you have accommodation, funds and the English ability to answer questions.
In case of changes, e.g., due to bad weather, follow the instructions provided by the airline.
In case of unclear, ask staff in uniform at the airport.