Liberal Democrat leader Sir Vince Cable has announced he will step down in May to make way for a “new generation”.
The 75-year-old said that assuming there is not an early general election the contest to succeed him will begin after forthcoming council elections.
Sir Vince, who plans to remain MP for Twickenham, had previously said there would not be a leadership election until “Brexit is resolved or stopped”.
In a statement, he said that “it is now clear that Brexit will be postponed, and very possibly stopped” and in an interview with the Daily Mail said that it “looks as if it will be a protracted process, and may never happen”.
The announcement comes ahead of the party’s spring conference in York, the city of his birth.
He said in a message to party members: “I indicated last year that once the Brexit story had moved on, and we had fought this year’s crucial local elections in 9,000 seats across England, it would be time for me to make way for a new generation.
“I set considerable store by having an orderly, business-like, succession unlike the power struggles in the other parties.
“So I wanted you, our members, to know that, assuming Parliament does not collapse into an early general election, I will ask the party to begin a leadership contest in May.”
He said this weekend’s conference would allow members to make the leadership contest the “biggest and most open leadership election British politics has ever seen”, adding: “It’s a real opportunity for our party to seize the radical and liberal centre of British politics.”
Mr Cable declined to name potential successors, but told the Daily Mail: “We’ve got several very good internal candidates – you can work out who they are. The worst thing I can do is to start promoting them.”
Anti-Brexit campaigner Gina Miller ruled herself out of a bid for the leadership, telling BBC Radio 4’s Today: “No, no, no, I’m definitely not doing that.”
May’s leadership contest will leave the Lib Dems searching for their fourth leader in four years.
Deputy leader Jo Swinson tweeted: “It has been an honour to work with Vince for a more open, liberal & tolerant Britain. He has helped @LibDems through challenges of last two years & led us to some of our best local election results in a decade – and I’m confident we’ll celebrate another strong set of wins in May.”
Layla Moran, one of the party’s 11 MPs, tweeted: “@vincecable I want you to know how grateful I am for all you’ve done. Thank you so much for your service to the Party and Brexit.”
The Lib Dems have languished in the polls and struggled electorally since going into government in coalition with the Conservatives in 2010.
Sir Vince lost his Twickenham seat in the mass defenestration of Lib Dem MPs at the 2015 General Election following their years of coalition with the Conservatives but he regained the seat in 2017.
He replaced Tim Farron as party leader in July 2017, who himself had replaced Nick Clegg two years earlier.