Kent councillor is alleged to have brought the party into disrepute in yet-to-be-broadcast TV interview

A Ukip councillor in Kent has been expelled for allegedly bringing the party into disrepute with “jaw dropping” remarks in a yet-to-be-aired television interview, it has been reported.

Rozanne Duncan is a councillor in South Thanet, the Kent constituency where Nigel Farage intends to stand in next year’s general election and in August let slip the party leader’s plans, which had hitherto been kept secret.

The latest incident comes as a poll shows that support for Ukip, and the personal approval ratings of its leader, is slipping. The survey, by Opinium for the Observer, show Farage’s rating below that of David Cameron and support for the party falling three points to 16%.

Ukip confirmed that Duncan was being expelled from the party but a spokesman refused to comment on reports from Kent Online that she was being thrown out over comments made in a television interview, described to the site by a source as “jaw-dropping”.

“Ukip is expelling Cllr Rozanne Duncan under rule 15 of its constitution for bringing the party into disrepute. She has 28 days to appeal,” said the spokesman. Duncan could not be reached for comment on Sunday.

The party has had a testing week. On Friday, Farage defended a former party candidate who stood down after being recorded referring to “poofters” and calling a woman with a Chinese name a “Chinky bird”. He also spoke of shooting “peasants” in comments made during a phone call that was recorded. It was claimed in his defence that he was on sedatives at the time.

Farage claimed Kerry Smith, who had been selected to stand for what has been called a winnable seat in South Basildon and East Thurrock, was simply using language that was common in the working-class area of east London from which he comes.

Farage told LBC: “I’m a bit sad, because Kerry Smith is a rough diamond. He’s a council house boy from the East End of London, left school early and talks and speaks in a way that a lot of people from that background do.” But he acknowledged he was not suitable to be a general election candidate.

It was reported earlier on Sunday that Ukip has told its activists not to use social media following a series of high profile gaffes. The party has changed its constitution to ban the unauthorised use of its logo and, in new “rules for online communication”, Ukip’s chairman, Steve Crowther, has warned those tempted to join Twitter: “My advice: just don’t.”

On Thursday last week, it emerged in a Channel 4 news report that a Ukip MEP, Janice Atkinson, who has criticised “feckless families” was being pursued for more than £2,000 in unpaid child support.