Sir David King stepped down yesterday as the Government's chief scientific adviser after seven years at the centre of the Whitehall machinery governing science-related topics as diverse as flooding, badger-culling, nuclear power and climate change.

As the top science adviser to the Prime Minister, Sir David gave Tony Blair the scientific ammunition to conduct a ruthless campaign of "contiguous culling" during the foot-and-mouth crisis of 2000-2001, when the Government took the deeply unpopular decision to kill all cattle on farms neighbouring an outbreak rather than to vaccinate unaffected livestock against the virus.

Sir David, 68, is also credited with convincing the former prime minister of the seriousness of climate change, saying publicly he thought it posed a more serious threat to people's lives than the threat of terrorism. He is also known to support the technology of genetic modification (GM), badger culling and the rebuilding of nuclear power stations – none of which has endeared him to environmentalists.

Sir David, a professor of physical chemistry at Cambridge University, has enthusiastically supported the need for scientists to identify long-term risks and opportunities as part of a wider "horizon-scanning" programme that looks beyond the relatively short lifetime of any one government. "We're not in the business of predicting the future. But we do need to explore the broadest range of different possibilities to help ensure government is prepared in the long term and considers issues across the spectrum of its planning," Sir David said.

But it was his comments on climate change in an editorial he wrote for the American journal Science that gave Sir David his high international profile, especially in the United States where the Bush Administration was in full denial of the mounting evidence linking global warming with the burning of fossil fuels.

"In my view, climate change is the most severe problem that we are facing today, more serious even than the threat of terrorism," Sir David wrote in an article clearly designed to influence political opinion in Washington. "The Bush Administration's strategy relies largely on market-based incentives and voluntary action ... But the market cannot decide that mitigation is necessary, nor can it establish the basic international framework in which all actors can take their place," he said.

Early in 2007 – international polar year – Sir David continued to make it clear that climate change was the most serious, long-term issue on the political agenda following the news that the polar ice is melting faster than predicted. "Global warming is the most challenging problem our society has ever faced up to. Ice is the canary in the coal mine of global warming," he said.

In his farewell speech last November to the Foundation for Science and Technology, Sir David made it clear he believes Britain may be losing an historic opportunity to exploit the benefits of GM technology – especially for the Third World – if it bans it outright.

"I would love to see Britain back at the forefront of positive use of GM technology. The process of GM technology should not be banned. The products of GM technology should be clearly monitored one by one," Sir David said.

Born in South Africa in 1939, Sir David came to Britain after he had been aggressively interrogated by the South African police for his outspoken opposition to apartheid. In 1974, he became a chemistry professor at Liverpool University and, in 1988, he took up a chair at Cambridge. He will continue to carry out research at Cambridge while taking up his new post as head of the Smith School of Enterprise and the Environment at Oxford University.

Sir David's successor is Professor John Beddington, 61, a population biologist at Imperial College London.

(By Steve Connor, The Independent, 01/01/2008)