Former business minister Jo Swinson is the new deputy leader of the Liberal Democrats, the party has said.
She was elected unopposed after no other candidates were declared, a spokesman said.
Ms Swinson, who regained her East Dunbartonshire seat from the SNP in the general election, had been an early favourite to succeed Tim Farron as leader following his resignation.
However, she opted instead to stand as deputy.
Announcing her decision over the weekend in a blogpost for Lib Dem Voice, Ms Swinson said she was “touched and flattered” that so many colleagues had encouraged her to run for leadership of the party
But she added: “Being the leader of a political party is a unique and all-encompassing job, even more than the roles of MP and minister that I have undertaken before. It should not be done simply to achieve status, to make a point, or to please others.
“Feminist that I am, I have of course wondered what a bloke in my position would do. It’s obvious. Most blokes in my shoes would run for leader like a shot. It’s true that my many years of encouraging women to have the confidence to go for that exciting new role have taught me that women often don’t go for things when they should. But just as often I have observed men going for the promotion when they shouldn’t. Just because a man would do it doesn’t make it the right thing to do.”
It means the contest is likely to be fought between Sir Ed Davey, Sir Vince Cable and Norman Lamb.
Mr Lamb told BBC Question Time last week he was “thinking about it”, while Vince Cable told The Independent he had ruled nothing out. It is possible either Sir Ed or Sir Vince will step aside for the other.
Senior figures in the party have suggested that either of these three figures could win the leadership contest, and much will now depend on the campaign, and who can set out the clearest vision for how the Liberal Democrats position themselves in a highly unusual political landscape, and who can best rebuild their base from the catastrophe of the 2015 election.
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies