Last October, the chair of the (UK) Advisory Council on the Misuse of Drugs (ACMD) was sacked by the health minister because he denounced government policies in public. New guidelines for the relation between scientific advice and policy making are being developed by the government. As you may expect, scientists do not seem to agree to some of the proposals. The dissent relates to a perceived restriction of scientific autonomy.
The most controversial clause is that independent scientific advisers and ministers should "work together to reach a shared position, and neither should act to undermine mutual trust".
Some scientists threaten to resign from advisory committees if the reform goes ahead.
Isn't there a lesson for the institutional setup of the IPCC? Remember, the IPCC's aim is to be scientific and political at the same time. It wants to come up with a shared position, and we have seen how the drive for political consensus muddies scientific findings.