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 yesterday.

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.

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.