The row between the UK Government and its drugs advisers escalated last night with the resignation of three more scientists.

Chemist Dr Simon Campbell, psychologist Dr John Marsden and scientific consultant Ian Ragan stepped down from the Advisory Council on the Misuse of Drugs (ACMD) following showdown talks with Home Secretary Alan Johnson.

The meeting was held amid the fall-out from the sacking of the government's chief drugs adviser Professor David Nutt (right) over his controversial remarks about cannabis, ecstasy and LSD.

“Today's resignations were regrettable but discussions with the ACMD today were constructive,” a home office spokesman said yesterday.

Dr Campbell said last night he did not want to comment on his resignation until he had formally written to the Home Secretary.