Scientific advisers to the government have demanded reassurances following the sacking of one of their colleagues.

Chairmen of various advisory committee and science academics have asked the government to reaffirm that it will respect the freedom and independence of its scientific advisers.

The move follows home secretary Alan Johnson's decision to sack Professor Nutt, chairman of the Advisory Council on the Misuse of Drugs (ACMD), after he claimed that alcohol and tobacco were more harmful than ecstasy and LSD, and challenged the decision to upgrade the classification of cannabis from C to B.

The guidelines that the government has been sent outline underlying fundamental "principles for the treatment of independent scientific advice".

Broadly they emphasise the need to respect the academic freedom and independence of government advisers, and for ministers to give "proper consideration" to the advice they receive. (Read the guidelines and signatory list in full).

Among the signatories are senior figures such as Professor Colin Blakemore, former chief executive of the Medical Research Council, who currently chairs the Food Standards Agency's general advisory committee on science.

He said: "The priority now must be to rebuild the confidence of the scientific community in the way the government, and indeed the opposition parties, treat scientific advice and those who provide it.

"If the government can sign up to this statement, which essentially summarises commitments that have been made in the past, I hope that we can press the 'reset' button on the relationship."

Liberal Democrats science spokesman Dr Evan Harris MP, who proposed drafting the statement, said: "The discontent in the scientific community about the treatment of David Nutt goes way beyond the members of the ACMD.

"It is necessary that the government reflects on the recent select committee [science and technology] report, which covers many of the issues set out in the statement, in order to win back the full confidence of their unpaid independent expert advisers."

In a separate development, members of the science and technology select committee wrote to Johnson demanding to know whether Professor Nutt had broken the terms of his contract or any codes of practice.

The MPs also wanted to know if the ACMD is still able to function following the sacking of Prof Nutt and the loss of two other experts who resigned in sympathy with him.