A $35 afternoon tea set served at the British pavilion at the Osaka Expo has left Japanese social media aghast at its perfunctory paper cups, sending Britain's embassy into damage-control mode.

"We have improved our service after some feedback saying we have failed to live up to expectations," a British Embassy official in Tokyo said in a video posted to X on Thursday.

"Afternoon tea is an important part of our tradition that symbolizes British culture," she said in Japanese.