Disclosure of decision to review operation of the Advisory Council on the Misuse of Drugs follows home secretary's sacking of David Nutt as the body's chairman

The home secretary, Alan Johnson, has placed the future of the expert body at the centre of the row over drugs policy in doubt by ordering a swift review of how it operates, the Guardian has learned.

The disclosure follows his decision to sack Professor David Nutt as chairman of the Advisory Council on the Misuse of Drugs (ACMD) on Friday after the scientist renewed his criticism of the government's decision to toughen the law on cannabis.

Today, in response to an emergency Commons question, Johnson said that he had agreed to the request from the ACMD for an urgent meeting and insisted that his decision to sack Nutt was taken because of the way he had conducted himself as chairman and not because of the council's policy advice on drugs.

Over the weekend, two other experts on the 40-strong body resigned in protest and members wrote to Johnson today warning more could follow and calling for urgent talks. It is thought that members could use a meeting next Monday to announce a mass resignation.

The purpose of the review of the ACMD, ordered in secret last month, is to "satisfy ministers" that the body is "discharging the functions" that it was set up to deliver and that it still represents value for money to the public. It will also ensure that the drug experts are operating in line with their terms of reference.

It is being carried out by Sir David Omand, a former permanent secretary at the Home Office.

The review is being rushed by Whitehall standards with the closing date for submissions at the end of this month. Omand has been asked to report back to ministers by early 2010.

Today in the Commons, Johnson said that the former home secretary Jacqui Smith had made clear her dissatisfaction when Nutt publicly disagreed with her decision not to downgrade ecstasy by comparing its dangers with those from horse-riding. She told him that she did not want it to happen again.

"Well, it has happened again," said Johnson. "On Thursday October 29 Professor Nutt chose, without prior notification to my department, to initiate a debate on drugs policy in the national media, returning to the February decisions, and accusing my predecessor or distorting and devaluing scientific research.

"As a result, I have lost confidence in Professor Nutt's ability to be my principal adviser on drugs."

He also downplayed the significance of the official review the ACMD is now facing. The home secretary said it had being undertaken in line with Cabinet Office guidelines as part of the round of quinquennial reviews of non-departmental bodies.

Johnson also insisted that he was not criticising science or scientists but acting in a particular case. He said the advice of independent scientific advisers was essential to the government. "The role of such advisers is to provide independent advice to government based on their professional scientific expertise.

"The role of government is to consider that advice carefully, along with all other relevant factors, and for this house to endorse or reject those decisions, where appropriate."

A letter from the ACMD to Johnson says the removal of Nutt raises for some members "matters of such seriousness as to raise the question whether they can, in good conscience, continue on the council".

It adds: "There is a consensus amongst members that a face-to-face discussion is the correct and proper forum to take these matters further. We will therefore continue as per the last two days and avoid discussion with the media, insofar as we can persuade members to comply.

Earlier Gordon Brown backed Johnson's decision to sack Nutt, who had accused ministers of "devaluing and distorting" the scientific evidence over illicit drugs by their decision last year to reclassify cannabis from class C to class B against the advice of the ACMD.

The prime minister's official spokesman insisted that Johnson's decision was based on an "important principle" that advisers should present advice to ministers but should not campaign against their policy decisions. While ministers were expected to take expert advice into account when considering an issue in the round, they were not bound to follow it.

"It would be regrettable if there were other resignations, but this is an important point of principle," he added. "The government is absolutely committed to the importance of having independent advice and evidence presented by advisory bodies."

Asked about the decision to sack Nutt, the spokesman said Downing Street was informed by Johnson of his decision but the prime minister took no part in it.

Johnson's decision follows the publication of a paper by the Centre for Crime and Justice at King's College London, based on a lecture Nutt delivered in July. He repeated his familiar view that illicit drugs should be classified according to the actual evidence of the harm they cause and pointed out that alcohol and tobacco caused more harm than LSD, ecstasy and cannabis.

He also argued that smoking cannabis created only a "relatively small risk" of psychotic illness.

Last week Johnson wrote to Nutt saying he no longer had confidence in him as chairman and asking him to consider his position; a Home Office spokesman said on Friday that Johnson was surprised and disappointed by Nutt's comments, which "damage efforts to give the public clear messages about the dangers of drugs".

Two members of the ACMD resigned yesterday in protest at Nutt's treatment. Another member told the Guardian that the experts were "planning collective action" against Johnson, adding: "Everybody is devastated. We're all considering our positions."

Nutt said there was "no future" for the council in its present form, and it is thought the group's members may use a meeting next Monday to announce a mass resignation.

In a letter in the Guardian, Johnson today accused Nutt of "campaigning against government policy" but insisted he was not forced out because of his opinions.

"Professor Nutt was not sacked for his views, which I respect but disagree with," he wrote. "He was asked to go because he cannot be both a government adviser and a campaigner against government policy."