The council has been accused of censoring questions from members of the public after a woman was banned from using the word 'propaganda' in a meeting.
Sharon Thomson submitted a question to the Sutton Council ahead of Monday night's full council meeting.
In her original question, which related to a leaflet distributed by Liberal Democrats earlier this year regarding parking problems in Belmont, she asked: "Was just pre-election propaganda or is it your genuine intention to resolve the ongoing parking issues?"
But when this was addressed to councillors at Monday night, recorded in the meeting's minutes and in the meeting's agenda, the words 'was this just pre-election propaganda or' were removed.
The decision to remove the offending words came from the council's monitoring officer but has been criticised by opposition councillors.
A council spokesman said: "In this instance part of the question was judged to attribute improper motives to others with the use of the word propaganda.
"Rather than rule the entire question out of order the monitoring officer removed the offending phrase, this did not affect the sense of the question which was answered by the chair of the environment and neighbourhoods committee."
Under rules set out in its constitution, the council is able to return questions the monitoring officer deems 'vexatious, irrelevant, improper, defamatory, frivolous or offensive'.
Councillor Tim Crowley, leader of Sutton's Conservative opposition, said: "Lots of people died to allow freedom of expression and freedom of speech. Of all the parties, the Liberal Democrats should be standing up for that.
"They may say it doesn't matter because the gist of the question hasn't been changed, but that's not the point. They've allowed use of worse words during council meetings in the past.
"I'm worried that this is a precedent which has been set to try to censor the residents of this borough when it suits the administration."