The former home secretary Charles Clarke has said the government should move to reassure its advisory committees that it will seriously consider their advice.

His comments come as the Home Secretary Alan Johnson defended his decision to sack his chief drugs adviser, Professor David Nutt, after he criticised the government's approach to cannabis and ecstasy. Mr Johnson says Prof Nutt was straying into politics. Two other members of the government's Advisory Council on the Misuse of Drugs resigned yesterday in protest at the dismissal.

Mr Clarke added that Gordon Brown made a "mistake... saying he was going to change the cannabis rules before the advisory committee had considered its position. I think that was an error."

Mr Clarke told the programme that government "should listen to advice and scientific opinion... I think science-based policy is a good way of trying trying to operate". But he added that if it had already decided a policy before taking expert opinion into account, it "should be straight up front".