Tourist visa

Yes, you have to apply for a Chinese tourist visa in advance. What's more, a Tibet Travel Permit is also needed after entering China.

Hi Maria,
Thank you so much for your email. I am so sorry to trouble you again.
As I said before I wish to go to Tibet . I understand according to the Tibet travel agent there is now a direct flight with China Eastern from London to Lhasa. If I took that will I still need a Chinese visa please. Also I am told you can be in transit for a certain number of hours in China without a Chinese visa. Can you please confirm and so sorry to trouble you again.

Yes, a Chinese visa is must as Tibet is a part of China. To enter Tibet, the travel agent will also need to help you to apply for a Tibet Travel Permit. Both of the two documents are necessary.