Tim Farron has dramatically quit as leader of the Liberal Democrats, saying he cannot face continued questions over his Christian faith.
Mr Farron, an evangelical Christian who was repeatedly questioned during the General Election campaign as to whether he believed gay sex was a sin, said his religion had made him a "subject of suspicion".
His shock announcement came just hours after the party's openly gay home affairs spokesman Lord Paddick said he was standing down citing "concerns about the leader's views on various issues".
In an emotional statement, Mr Farron, who had been in post less than a year, said he had been unable to reconcile his Christian faith with the demands of leading a "progressive, liberal" party.
"The consequences of the focus on my faith is that I have found myself torn between living as a faithful Christian and serving as a political leader," he said.
"A better, wiser person than me may have been able to deal with this more successfully, to have remained faithful to Christ while leading a political party in the current environment.
"To be a political leader - especially of a progressive, liberal party in 2017 - and to live as a committed Christian, to hold faithfully to the Bible's teaching, has felt impossible for me."
Former business minister Jo Swinson, who regained her East Dunbartonshire seat from the SNP in the election, was immediately installed as the bookies' favourite to succeed him and become the party's first female leader.
Mr Farron faced intense criticism during the election campaign for failing to answer questions about his position on homosexuality.
While he made it clear he supported equal marriage and LGBT rights, he initially declined to say whether he believed gay sex was a sin.
After days of pressure to clarify his stance on the issue, he finally made clear he did not, but continued to face questions in interviews.
In his statement, Mr Farron said the continued questions over his faith showed people in Britain were "kidding ourselves" if they thought they were living in a tolerant liberal society.
"I'm a liberal to my finger tips, and that liberalism means that I am passionate about defending the rights and liberties of people who believe different things to me," he said.
"Even so, I seem to be the subject of suspicion because of what I believe and who my faith is in. In which case we are kidding ourselves if we think we yet live in a tolerant, liberal society."
Mr Farron said that he would carry on as party leader until Parliament breaks for the summer recess next month, when an election for a new leader would be held.
While the Lib Dems endured a disappointing General Election - gaining just three seats - Mr Farron's position had not been thought to be under immediate threat.
His resignation means that he follows Ukip's Paul Nuttall as the second party leader to resign in the wake of the election result.
Lib Dem MP Tom Brake said his decision to go was "very sad".
"Under his leadership party membership doubled and number of MPs increased by 50%," he said.