The decision was announced by party supremo and state Finance Minister K M Mani after a high-level meeting of party leaders here.
Talking to reporters, Mani said George was also suspended from party committees, but would continue to be a member of the party.
He said the latest action was taken in the wake of repeated anti-party activities and violation of party discipline by George, who has been highly critical of the party leadership.
Keeping George as a member of the party will tie him under the ambit of anti-defection law. The party has nine MLAs, including him.
George was removed from the post of Chief Whip on April 8 by Chief Minister Oommen Chandy as per the demand of KC-M after parleys to avert the action failed.
George had been making public statements against UDF leaders that led to removal from the Chief Whip post.
Rift between George and party leader Mani, who was facing charges of corruption in bar bribery scam, reached a flash point after the former attacked the latter over presentation of Budget.
Meanwhile, George continued his tirade against KC-M and said he would move the High Court against Mani for holding dual positions as state Finance Minister and party Chairman "against" party rules.
