Chinese police have detained six foreign activists for a free Tibet, including one Briton, after they unfurled a banner down the side of the Great Wall demanding the end to Chinese rule in the restive Himalayan region.

Two activists abseiled over the Mutianyu section of the wall in a two-hour protest timed to coincide with celebrations in China surrounding the one-year countdown to the start of the Beijing Olympics on August 8 next year.

The banner read: "One World, One Dream, Free Tibet 2008" in both English and Chinese.

The group, including 22-year-old Briton Peter Speller, one Canadian and four Americans, was detained by local police and efforts by British consular officials to gain access to Mr Speller had yet to receive a response by the end of the day.

Tenzin Dorfe, deputy director of Students for a Free Tibet, which helped to organise the protest, said: "The Chinese Government is exploiting the Olympics to gain acceptance as a world leader.

"By protesting at the Great Wall, the most recognisable symbol of Chinese nationhood, we’re sending a clear message that China’s dream of international leadership cannot be realised as long as it continues its brutal occupation of Tibet."

China has ruled Tibet since 1951 after its troops entered the region a year earlier to stake its claim to the deeply Buddhist region that Beijing says has been a part of Chinese territory for centuries.

Tibet’s spiritual and temporal leader, the Dalai Lama, fled his homeland in 1959 and has since lived in exile in India.

The international movement to regain independence for Tibet has vowed to maintain pressure on China in the lead-up to the Olympics with unauthorised protests on the mainland as well as demonstrations around the world.

In April, five Americans from Students for a Free Tibet were expelled from China after they unfurled a similar banner at the Chinese base camp on Mount Everest.

Beijing officials have announced that the Olympic torch will travel enter Tibet after ascending the southern slope of Mount Everest in Nepal.

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