The government's chief drug advisor has been sacked after failing to give the public "clear messages".
Professor David Nutt, of the Advisory Council on the Misuse of Drugs (ACMD), was sacked after saying cannabis did not cause major health problems.
Home secretary Alan Johnson asked Prof Nutt to quit the ACMD because his actions "undermine its role and scientific independence".
"In a letter he expressed surprise and disappointment over Prof Nutt's comments which damage efforts to give the public clear messages about the dangers of drugs," a Home Office spokesman said.
"We fully support the work of the ACMD and remain committed to considering the independent advice and evidence it and other advisory bodies provide to the government. However the clear role of the chair of the ACMD is to provide independent scientific advice and not to lobby for changes in policy.
"We remain determined to crack down on all illegal substances and minimise their harm to health and society as a whole."
Prof Nutt had claimed the drug should have remained categorised as a class C substance. Former home secretary Jacqui Smith returned cannabis to class B status despite all medical and official advice pointing against it.
His dismissal comes after a series of comments downplaying the danger posed by many drugs. Prof Nutt claimed taking ecstasy was less dangerous than riding a horse.
"We have to accept young people like to experiment - with drugs and other potentially harmful activities - and what we should be doing in all of this is to protect them from harm at this stage of their lives," he said.
"We therefore have to provide more accurate and credible information. If you think that scaring kids will stop them using, you are probably wrong."