Three of the biggest sponsors of the Beijing Olympics have scaled back their plans for next week’s Japanese leg of the torch relay amid mounting fears of violent antiChinese protests, The Times has learnt.

In the first signs of a wobble by the Games’ commercial backers after a wave of demonstrations, Coca-Cola, Samsung and Lenovo will not field their logo-covered vehicles as the flame makes its way through Nagano.

The decision emerged hours after religious leaders at a Buddhist temple in Nagano, the host city of the 1998 Winter Olympics, caused major disruption to the route by withdrawing as the starting point on April 26. Priests at the Zenkoji temple, whose imposing bell was rung to open the Nagano Games, said it was a reaction to “indiscriminate killing in Tibet”.

Yasuo Fukuda, the Japanese Prime Minister, playing host to Yang Jiechi, the visiting Chinese Foreign Minister, said that the move was “unfortunate”.

About 3,500 police and security personnel have been drafted in and at least one school has declared an impromptu holiday to protect its pupils. About 2,000 Chinese students from around Japan are expected in Nagano, raising the risk of clashes with ultra-right nationalist groups.

The torch has encountered protests on almost every leg of its global tour. The worst clashes between police and pro-Tibet demonstrators occurred in London, Paris and Delhi.

The withdrawal of branded vehicles from the Japan leg is the first example of sponsors playing down their association with the torch, which has become a magnet for activists. The adverse public reaction has forced Olympic sponsors to implement crisis management strategies devised when Beijing was controversially awarded the Games in 2001, according to experts. The aim is to protect their multimillion-pound investments and ensure no lasting damage to their brands.

“They have always known that it would be tough with China hosting the Olympics but the risks have escalated,” said Damien Ryan, a Hong Kong-based adviser to Olympic sponsors. “Now they’re having to alter their communications strategy on the run because the situation is changing fast. But they’ve done their research. There are responses to scenarios from A to Z that can be rolled out.”

Coca-Cola has come under intense lobbying from Dream for Darfur, the group led by the Hollywood actress Mia Farrow, which staged protests outside its annual shareholder meeting this week. The Atlanta-based company and 18 other Olympic sponsors are the target of its campaign, calling for people watching the Games to change the channel or turn off their TVs during their advertisements.

Coca-Cola has responded to activists by saying it has pledged more than $5 million to help to solve Darfur’s water issues and more than $7 million over the next three years towards humanitarian efforts in Sudan. It also plans to meet at least one pro-Tibet group.

But it has been a sponsor of the Olympics for 80 years, toughing it out through the 1936 Nazi Games, the 1968 Tlatelolco massacre in Mexico, the slaughter of Israeli athletes in Munich in 1972 and the 1980 Moscow boycott. Beijing 2008 will be no different, according to industry watchers.

“There have been many wobbles but the Olympic rings are the most recognised symbol on the planet and sponsors think there is more to gain than to lose,” said Kevin Roberts, editorial director of Sport Business Group.