He said it was “more likely” that the alleged victim was a prostitute whose “punter … didn’t pay”.
Mr Slator was suspended from Bromley’s Conservative group in January and the council voted to condemn his comments.
He later apologised, saying he was “not ashamed to admit that I am fallible, and I have made a mistake”. He also deactivated his Twitter account.
The councillor also said he had signed up for a course about online interaction, and as a councillor, he had “a responsibility to reflect more deeply on what I say and post online”.
A Conservative party spokesperson said Mr Slator had now been expelled.
They said: “The Conservative party has an established code of conduct and formal processes where complaints can be made in confidence. This process is rightly confidential. Following the conclusion of this process, cllr Slator has been expelled.”
Mr Slator told the BBC he was “disappointed” by the decision and would be “submitting an appeal in due course”.
At the time, Labour group leader Simon Jeal called Mr Slator’s comments “revolting”, while Colin Smith, the Conservative leader of the council, said his comments were “beyond the pale”.
The Independent has contacted Mr Slator and Bromley and Chislehurst Conservatives for comment.
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