The Welsh Liberal Democrats' leader has angrily accused fellow MPs of "violating" their party's values in forcing Charles Kennedy to resign.
Charles Kennedy says the new leader will inherit a strong party
Mr Kennedy bowed to pressure from his parliamentary party on Saturday and quit after admitting his drink problem.
Montgomeryshire MP Lembit Opik said his colleagues' action was "the political equivalent of self-harming," which left "deep scars" and a resentful party.
But the resignation was welcomed by Cardiff Central MP Jenny Willott.
Announcing that he would be quitting immediately, Mr Kennedy said he would not put his name forward for the leadership election he had called, because of a lack of support from his MPs.
Mr Opik accused fellow MPs of having forced Mr Kennedy out without giving party members a say in a ballot.
"They've got what they wanted and we lose the most successful party leader we've had for 83 years," said Mr Opik.
"It has been divisive and I've got some very strong words to say which I'll now share quietly and privately about the performance of some of my colleagues.
"I think they have violated the values of the party and crucially they have given their impression that their words and their views are more important than the electorate which chose him in the first place, and I don't think that's very constitutional.
"There are many deep scars and a lot of resentment, primarily among the membership, who are bewildered by what's happened."
Mr Opik appealed for a "unifying" leadership contest. "I think that we've done the damage to ourselves. It's been the political equivalent of self-harming in the last few weeks.
"We now have the chance for that to stop, as long as colleagues behave maturely. The very worst thing they can do is behave in a leadership election the way they have carried on towards Charles Kennedy."
Mr Opik ruled himself out of this election, but said he would run for leader next time. He also confirmed that he would support Mark Oaten, if the Winchester MP decided to stand.
Ms Willott, who became Cardiff Central MP last year, said she had huge sympathy for Mr Kennedy's health problems, but it was time for him to quit.
She was among 25 Lib Dem MPs who signed a letter calling for him to stand down, although she said she had not decided who to support now.
She said: "I feel that his position was untenable. He had lost the support of most of the parliamentary party.
"I felt that Charles on his best form was the best party leader, but he was no longer on his best form.
"For me, Charles didn't have enough momentum to drive the party in the best direction."
Mike German, who leads the Lib Dems in the Welsh assembly, said he was disappointed, but Mr Kennedy's lack of support among Lib Dem MPs made his departure inevitable.
Peter Black, a South West Wales Assembly Member who had urged him to quit, said: "It came to a situation where his leadership had run its course.
"We now need someone to take the party forwards, in order that we can continue to build on our successes and achievements."