Margaret Thatcher refused a request to fly a panda in the back of her Concorde when she visited Washington for her first summit with Ronald Reagan, according to papers released on Friday.
The then prime minister was drawn into the scheme in January 1981, the same month that Reagan was inaugurated, when the Smithsonian Institution in Washington appealed to London Zoo for the loan of its male panda.
The president of the London Zoological Society, Solly Zuckerman, seized on the opportunity to create a publicity stunt with the help of the prime minister.
"Lord Zuckerman sees this as a signal demonstration of the special relationship and would be very happy to time the announcement of the loan or the delivery of the panda in any way that the prime minister thought would be most likely to benefit Anglo-American relations," cabinet secretary Robert Armstrong wrote.
"He even suggested that the prime minister might like to take the panda in the back of her Concorde, when she goes to Washington next month," he added, according to papers released by the National Archives in Kew, London.
The "Iron Lady" was not convinced, however, that she should be involved in promoting London Zoo's efforts to bring a new mate to a female panda.
"Lord Z knows more about pandas than I do -- I am sure he can arrange these things," she said in a handwritten note.
Her private secretary, Clive Whitmore, replied to Zuckerman: "She has commented that she is not taking a panda with her -- 'Pandas and politicians are not happy omens!'"