It's as clear and chilling a statement of intent as you're likely to read. Scientists should be "the voice of reason, rather than dissent, in the public arena". Vladimir Putin? Kim Jong-un? No, Professor Ian Boyd, chief scientific adviser at the UK's Department for Environment.

Boyd's doctrine is a neat distillation of government policy in Britain, Canada and Australia. These governments have suppressed or misrepresented inconvenient findings on climate change, pollution, pesticides, fisheries and wildlife. They have shut down programmes that produce unwelcome findings and sought to muzzle scientists. This is a modern version of Soviet Lysenkoism: crushing academic dissent on behalf of bad science and corporate power.

Writing in an online journal, Boyd argued that if scientists speak freely, they create conflict between themselves and policymakers, leading to a "chronically deep-seated mistrust of scientists that can undermine the delicate foundation upon which science builds relevance". This, in turn, "could set back the cause of science in government". So they should avoid "suggesting that policies are either right or wrong". If they must speak out, they should do so through "embedded advisers (such as myself), and by being the voice of reason, rather than dissent, in the public arena".

Shut up, speak through me, don't dissent – or your behaviour will ensure that science becomes irrelevant. Note that the conflicts between science and policy are caused by scientists, rather than by politicians ignoring or abusing the evidence. Or by chief scientific advisers.

In an online question and answer session hosted by his department, Professor Boyd maintained that 50% of tuberculosis infections among cattle herds are caused by badgers. He repeated the claim in an official document called Science to Inform TB Policy. But as the analyst Jamie McMillan points out, the figure has been sexed up from inadequate data. Like the 45-minute claim in the Iraq debate, it is "spurious, simple to take on board, and crucial in convincing parliament".

The badger cull as a whole defies the findings of the £49m study the previous government commissioned. It has been thoroughly dissected by the leading scientists in the field, which might explain why Boyd is so keen to shut them up. It's one of many ways in which his department has binned the evidence in setting its policies.

Yesterday Boyd's boss, environment secretary Owen Paterson, told the Tory party conference not to worry about global warming. "I think we should just accept that the climate has been changing for centuries." A few weeks ago on Any Questions, he managed to repeat 10 discredited claims about climate change in one short contribution.

His department repeatedly misrepresents science to appease industrial lobbyists. It claimed that its field trials of neonicotinoid pesticides on bees showed that "effects on bees do not occur under normal circumstances". Hopelessly contaminated, the study was in fact worthless, which is why it was not submitted to a peer-reviewed journal.

Similar distortions surround the department's refusal to establish meaningful marine reserves, its attempt to cull buzzards on behalf of pheasant shoots, and its determination to allow farmers to start dredging streams again, turning them into featureless gutters.

There's one consolation: Boyd, in his efforts to establish a tinpot dictatorship, has not yet achieved the control enjoyed by his counterparts in Canada. There, scientists with government grants working on any issue that could affect industrial interests – tar sands, climate change, mining, sewage, salmon farms, water trading – are forbidden to speak freely to the public. They are shadowed by government minders and, when they must present their findings, given scripts to memorise and recite. Dozens of turbulent research programmes and institutes have either been cut to the bone or closed altogether.

In Australia, the new government has chosen not to appoint a science minister. Tony Abbott, who once described man-made climate change as "absolute crap", has already shut down the government's climate commission and climate change authority. But at least Australians are fighting back: the climate commission has been reconvened as an NGO, funded by donations. In Britain we allowed the government to shut down the Royal Commission on Environmental Pollution and the Sustainable Development Commission with scarcely a groan of protest.

David Cameron's government claimed that the tiny savings it made were required to reduce the deficit. Yet somehow it manages to fund a lavish range of planet-wrecking programmes. The latest is the Centre for Doctoral Training in Oil and Gas, just launched by the Natural Environment Research Council. Its aim is "to support the oil and gas sector" by providing "focused training" in fracking, in exploiting tar deposits, and in searching for oil in polar regions. In other words, it is subsidising fossil fuel companies while promoting climate change. How many people believe this is a good use of public money?

To be reasonable, when a government is manipulating and misrepresenting scientific findings, is to dissent. To be reasonable, when it is helping to destroy human life and the natural world, is to dissent. As Julien Benda argued in La Trahison des Clercs, democracy and civilisation depend on intellectuals resisting conformity and power.

A world in which scientists speak only through minders and in which dissent is considered the antithesis of reason is a world shorn of meaningful democratic choices. You can judge a government by its treatment of inconvenient facts and the people who expose them. This one does not emerge well.

Twitter: @georgemonbiot A fully referenced version of this article can be found at monbiot.com