The man ousted as a Ukip candidate by defector Douglas Carswell has warned the party risks alienating its core membership.
Roger Lord had been selected to stand at the next general election but was sidelined after Mr Carswell announced he was leaving the Conservative Party and standing down from Parliament, forcing a by-election in Clacton, Essex.
Mr Lord, a farmer, has now resigned from Ukip and from his role as a county councillor.
He ruled out standing against Mr Carswell but said that if rumours of further high-profile defections prove true, Ukip leaders risk changing the nature of the party.
Mr Lord added: “There are loads of good people within Ukip who have worked hard for a long time and deserve to be shown a degree of respect.
“If the leadership continues to demean those people and sweep candidates aside, it could backfire.
“I may well be just the first of many to be trampled on in this way. Voters certainly won’t be impressed by people being moved around like chess pieces.”
It has been claimed that eight Tory MPs have “lunched” with Ukip and that euro-sceptic Labour MPs may also be considering defecting.
But Mr Lord added that many existing members may dislike the approach and people who he had recruited to Ukip locally may be reluctant to back Mr Carswell.
A Ukip spokesman previously said Mr Lord had never been the by-election candidate for Clacton. Voting takes place on October 9.