Britain's pro-EU Liberal Democrats on Friday (13) said they would elect a new leader to replace Jo Swinson, who lost her seat in the general election.

Swinson's deputy Ed Davey and party president Sal Brinton will become joint acting leaders and a leadership election will take place in the new year, the Lib Dems said.

The party looked set to win no more seats than in the last election in 2017, despite a huge increase in support in European Parliament elections earlier this year.

Swinson said her own loss in East Dunbartonshire in western Scotland, and the victory for Prime Minister Boris Johnson's Conservatives, was "hugely disappointing".

She defended her campaign, focused on a promise to reverse Brexit, saying: "We were honest about what we believe in and what we were trying to achieve.

"This is clearly a setback for liberal values.

"But there are millions of people across the country who believe in them. By coming together to fight for them, we can create a positive future."

Brinton added: "I want to thank Jo Swinson for her honest and fearless leadership of the Liberal Democrats.

"In the weeks ahead we will elect a new leader and our party will continue to be the rallying point for anyone who believes in a country where everyone has the chance to get on in life."

Swinson lost her seat to the Scottish National Party (SNP).

(AFP)