Giant pandas are to return to the UK for the first time in 17 years after an agreement was signed with China today.

The pair of seven-year-old pandas, Tian Tian and Yangguang, will arrive at Edinburgh zoo this year, marking "the culmination of five years of political and diplomatic negotiation at the highest level" according to the Royal Zoological Society of Scotland. The agreement was witnessed by Nick Clegg and the vice premier of China, Li Keqiang.

The ambassador of China to the UK, Liu Xiaoming, said: "Pandas are a Chinese national treasure. This historical agreement is a gift to the people of the UK from China. It will represent an important symbol of our friendship and will bring our two people closer together."

"The kind gift of a loan of a breeding pair of giant pandas, Tian Tian and Yuangguang, is a sign that we can co-operate closely on a broad range of environmental and cultural issues, as well as commerce," said Clegg.

The UK's last giant panda, Ming Ming, was housed in London Zoo until 1994, when she was moved back to China.

The agreement marks a return to a custom abandoned in recent years. China traditionally presented pandas to other nations to improve foreign relations in what was known as "panda diplomacy". But the Chinese government reportedly called an end to the practice in 2007, when it said pandas would only be lent out for breeding and biological research.

Between 1957 and the 1980s, China gave more than 20 pandas to countries around the world. Just last September, the death of a Chinese giant panda in a Japanese zoo caused a diplomatic stir, and the gift of two giant pandas to Taiwan in 2008 was interpreted variously as a diplomatic push for more control over the self-governing territory or a peace offering aimed at strengthening relations.