The Liberal Democrat deputy leader, Jo Swinson, has been tipped as the frontrunner to replace the party’s outgoing leader, Vince Cable, who has announced plans to step down from the party in May.

Cable, a former business secretary in the coalition government, announced that he would set a timetable for his departure at the party’s spring conference this weekend.

Three MPs were expected to be in the running: Swinson, the former cabinet minister Ed Davey and the party’s education spokeswoman, Layla Moran.

Swinson, a coalition business minister, was highly likely to announce her candidacy, according to multiple sources. One, who is close to Swinson, said: “Jo loves the party and is passionate about wanting it to succeed. She hears the calls for her to stand very clearly, and I would put money on her going for it.”

She has been a vocal campaigner on maternity rights and equal pay. She became embroiled in a row about parliamentary maternity leave when Conservative whips broke a pairing agreement when she had just given birth to her second child.

The row, in which the Conservative chair, Brandon Lewis, voted on a close amendment when whips had agreed he would abstain to cancel out Swinson’s absence, kickstarted the introduction of proxy voting for MPs on parental leave.

Davey, the energy and climate change secretary in the coalition government, is said by party sources to have undertaken the most direct preparation for a tilt at the leadership. They said they expected his pitch to be about the renewal of liberalism in the face of the threat from darker, populist forces.

In an article for the New Statesman, Davey said liberal leaders had “to embrace the emotions of voters” and loudly champion progressive causes, such as land tax, electoral reform and climate change.

“From air pollution to sustainable, quality food, a full-blown green health agenda could be very popular,” he wrote.

Both Davey and Swinson lost their seats in the 2015 general election but regained them two years later, Davey in Kingston and Surbiton, and Swinson in East Dunbartonshire.

Moran, a former teacher elected to Oxford West and Abingdon in 2017, is the first MP of Palestinian descent and is also likely to have a good chance of success should she run for the leadership. However, Lib Dem sources were uncertain whether she would, saying her lack of experience might mean she would decline to put herself forward.

“She is the most interesting candidate, a fresh face with real-world experience, but she has a very small majority and may feel it is not the right time,” one source said.

Party reforms put forward by Cable, if passed at the spring conference, would allow non-MPs to stand for the leadership. However, one party source said they were a “red herring” and it was highly unlikely that a non-MP would be elected as leader.

What is likely to have more effect on the race is the new composition of the party membership. One party official estimated that 70% of members had joined since 2015, and a large number who joined since the EU referendum had never voted in a leadership election.

Senior party figures, such as Nick Clegg, are likely to stay neutral in the race.

Party sources said those two factors, combined with Cable’s plan to allow votes from registered supporters, meant there was a large degree of uncertainty about who would win.

Cable’s successor faces challenges over the coming months, over issues such as the party’s post-Brexit direction and the formation of the Independent Group (TIG) of MPs, involving former Conservative and Labour supporters of a second referendum. There has been speculation TIG could form a coalition or forge an electoral pact with the Lib Dems.