Liberal Democrat leader Jo Swinson has insisted she is not losing control of party candidates after a standard bearer stood down in a key marginal.
The comments came after Tim Walker said he would not contest Labour-held Canterbury because he did not want to split the Remain vote.
Ms Swinson insisted the Lib Dems would field another candidate in the Kent seat.
She said the party would also continue to stand against former Tory Cabinet minister David Gauke despite his outspoken criticism of Prime Minister Boris Johnson.
Asked if she was losing control of Lib Dem candidates, Ms Swinson told the PA news agency: “No. Clearly as Liberal Democrats we are committed to stopping Brexit.
“We have a healthy debate within the party and some candidates have made their own decisions.”
Ms Swinson was speaking as she visited a boxing gym in north London that trains youngsters in order to deter them from gang culture.
At the Total Boxer centre in Crouch End, Ms Swinson was shown punching moves by an instructor in a boxing ring.
For the boxing class, the Lib Dem leader sported a T-shirt with a spider on it and the words “Girly Swot”.
Ms Swinson told PA the spider was a tribute to Supreme Court judge Lady Hale who wore a spider broach when she delivered a judgment that proroguing Parliament in September had been unlawful.
Ms Swinson said she was “reclaiming” the phrase “girly swot”.
She said: “I was looking for a T-shirt for the ring and I thought it would do the job.”
Mr Johnson used the phrase to refer to ex-PM David Cameron.
Ms Swinson was at the gym to highlight a Lib Dem pledge to put £500 million a year into combating knife crime.
Mr Walker was due to contest Labour-held Canterbury but said he had asked his local party to withdraw his nomination papers as he wanted “no part” in allowing a Tory Brexiteer to win the seat.
Guy Kiddey, Lib Dem candidate in the High Peak constituency, said he will stand down and resign his membership of the party unless Mr Walker receives an apology.
In a statement on Twitter, Mr Kiddey wrote: “Many Lib Dem candidates are standing in marginal seats. We are all as torn as Tim Walker, but none of us is as noble.
“I’ve never met Mr Walker but, as a distant colleague, I stand by him and his decision to stand down.
“I know that, if I campaign hard in High Peak, I will split the vote and the Tory will win.
“Though I could probably achieve the party’s best-ever result up here, perhaps increasing the Lib Dem vote share five-fold compared to 2017, a mere happy statistic is a definite second to keeping a Tory party that threatens to be worse than Margaret Thatcher’s out of office.”
Mr Kiddey said he received an email from James Gurling, chairman of the Lib Dem election campaign, who said he was writing to inform candidates that “disciplinary action” had been instigated against Mr Walker.
“I was, and am, appalled at this response. So is my now former election agent, who has resigned from the Lib Dems.
“This means that I am, in the absence of a replacement, not legally able to stand as a candidate in High Peak in the coming election, as I do not wish to be my own agent.
“I will not seek this replacement unless the party retracts its implicit threat to candidates, drops its intended disciplinary proceedings against Mr Walker, and apologises unreservedly.
“I doubt it will, in which case I too will stand down and resign my membership, and I will vote Labour,” he said.