Councillor Paul Aitken has decided that he will now be an independent councillor and no longer a Conservative.
It is understood that Mr Aitken, who became the first Tory councillor elected in Barrhead in 25 years last May, quit following a series of disagreements between Mr Aitken and fellow Tory councillors in East Renfrewshire.
Mr Aitken says he will now sit as an Independent, however Labour have called on him to resign from the local authority and stand for re-election.
In a statement Councillor Aitken said: “I would like to advise East Renfrewshire Council that going forward, and with immediate effect, I will be serving my constituents in Barrhead & Uplawmoor as an Independent councillor and that I will no longer have an association with a political party.
“I have always felt that the real bosses of local councillors are their constituents, not their political parties. Local councillors should not feel bound by party diktat in relation to what they may say or how they may vote.
“Local councillors answer to their constituents.
“That is how local democracy should work.
“From now on, I will be privileged to serve the people of Barrhead and Uplawmoor as an Independent Councillor.”