"I am raising my voice," said the politician who has characterised environmentalism as an ideology as dangerous as communism.

"Can we allow certain political movements that want something else other than liberty to profit from an hysteria which has been born?" Klaus asked.

"Above all, it is necessary to determine if the impact of man on global climate change is such that it justifies this hysteria," he added.

Klaus, as well as being a well known eurosceptic and a fan of former British premier Margaret Thatcher, has now lined up alongside the US sceptics in the climate change debate.

During the presentation at Prague's Slavia Cafe in Prague, a favourite haunt of intellectuals, Klaus called for a rational debate over climate change.

He called on the public to "open its eyes faced with a dangerous manipulation" by those who, according to him, want to "limit free thinking and decision making."

The local branch of the environmental group Greenpeace organised a protest in front of the cafe with a banner "A flat, not round, world," in parody of Klaus' latest work.

"With these protesters, we can see that those who have taken up this theme are not scientists," joked the 66-year old Klaus.

Klaus, a trained economist and former right-wing prime minister, was recently invited to present his climate change views to the US Congress as a counterweight to those of former US vice-president Al Gore.

During his speech, Klaus argued that environmentalism represented just as big a danger to freedom as communism.

Klaus's publisher, Marek Pecinka, characterised his book as "an effective antidote against the gossip of Al Gore."

In a speech last month, Klaus said that while he recognised concerns about the environment were legitimate, his problem with environmentalism as an ideology.

"Environmentalism only pretends to deal with environmental protection," he told the right-wing libertarian think-tank the Cato Institute in Washington.

"Behind their people- and nature-friendly terminology, the adherents of environmentalism make ambitious attempts to radically reorganize and change the world, human society, our behavior, and our values," he added.

A Czech edition of Gore's book "An inconvenient truth," which was made into an Oscar winning film of the same name, was released this week.

It received financial support from the Czech environment ministry, headed by local Green Party leader and Klaus adversary, Martin Bursik.

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