Argyll and Bute MSP, Michael Russell, has called for the 'immediate' revocation of the decision to close Thomson Court day centre.
In a letter to Christina West, Chief Officer of the Argyll and Bute Health and Social Care Partnership, Mr Russell said: "I write in connection with the decision to close the above facilities [Thomson Court day centre and Struan Lodge] made by the Integrated Joint Board.
"You will be aware that at the Bute and Cowal Area Committee held in Rothesay on Tuesday a member of your staff admitted that the 'consultation' process announced regarding these closures was a sham and confirmed that the decision to close had been made on June 22 before the 'consultation' was even announced.
"It is utterly unacceptable for an accountable public body to behave in this way. Consultation means consultation. it does not mean attempting to perpetrate a confidence trick on the community by using warm words to cover up actions which are strongly opposed by those to whom the body is accountable.
"In addition it does not mean presenting figures and information which is not verified and robustly refuted as if it had official imprimatur."
Mr Russell continued: "The IJB has got off to a very bad start. There is no doubt that the public will refuse to place its confidence and trust in a body which operates in this way, and that would bode very ill for the delivery of vital health and community care services in our area.
"I therefore write to ask that you immediately revoke the closure decision (which I also understand will save virtually no money in this financial year), apologise openly to the communities affected for operating in this way, undertake a review to ensure that your governance is radically improved and confirm that there will be no repetition of such actions."