Animal campaigners today urged Prime Minister Gordon Brown and First Minister Alex Salmond not to support a zoo's plans to bring in a giant pandas from China.

Earlier this month the Royal Zoological Society of Scotland (RZSS) announced it had been working with officials in China to bring a breeding pair of the creatures to Edinburgh Zoo.

But an international coalition of animal welfare groups has written to both Mr Brown and Mr Salmond in protest.

Organisations including Advocates for Animals, the Born free Foundation, People for the Ethical Treatment of Animals and the World Society of the Protection of Animals have signed up to the letter expressing their "concern" about the proposal.

The letter said: "If Edinburgh Zoo or the RZSS wishes to help giant pandas, this should be by supporting in situ conservation in Chinese panda reserves, along with moves to preserve the animals' natural habitat."

Representatives from Edinburgh Zoo recently visited China, where they signed a letter of intent signifying an initial commitment to bring giant pandas to the zoo.

It has been proposed that the breeding pair would be on loan to the RZSS for ten years and it is hoped they would give birth to cubs during that time.

But the animal welfare groups claimed it was their understanding that no captive bred giant panda had ever been successfully reintroduced into the wild.

And they said: "Any animals bred at Edinburgh Zoo would most likely be condemned to spend their entire lives in captivity."

The letter also stated that the panda plan could be regarded by some as a "diplomatic gift" of animals - a practice the groups claimed was "widely discredited and is nothing more than a deplorable activity from a bygone age".

They concluded: "We urge the Government not to support or promote any plans to lease giant pandas."

Edinburgh would be only the eighth zoo in the Western hemisphere to care for the species if the project goes ahead.

Zoo chiefs have argued that looking after the endangered animals could benefit conservation.

David Windmill, the chief executive of RZSS - which owns Edinburgh Zoo - said the giant pandas would be on loan from the Wolong Research Centre in China.

He argued: "Having a population in zoos and reserves is integral to sustaining the giant panda population as a whole.

"Zoos are able to invest valuable resources into researching the biology of this species.

"This information is then shared with conservationists in China to help them gain a greater understanding of the wild population."

He said any cubs born at Edinburgh Zoo would eventually go to Wolong, where programmes to reintroduce giant pandas into the wild will begin in the next couple of years.

Mr Windmill said claims that no captive bred giant panda had ever been successfully released into the wild referred to the attempted reintroduction of a male, who is thought to have been attacked and killed by another wild male.

And he added: "When new attempts are made it is likely that females will be reintroduced as they are less aggressive."

The RZSS has also donated £10,000 to the disaster relief fund set up by the China Wildlife Conservation Association, who look after all the panda reserves in the Sichuan province.

They gave the funds after the Wolong Nature Reserve was affected by the earthquake there, with five members of staff killed and two pandas from the reserve missing.