Jo Swinson has said she will lead a movement to tackle "nationalism and populism" after confirming she will stand for the Liberal Democrat leadership.

The party's deputy leader said she was the right person to lead the "liberal movement" as she entered the contest to succeed Sir Vince Cable.

The leadership contest comes as the Lib Dems received an opinion poll boost, with a YouGov study suggesting they are now the most popular party.

A new Lib Dem leader will be in place on July 23 after Sir Vince announced his decision to stand down earlier this year, and Ms Swinson will face competition from former cabinet minister Sir Ed Davey.

Ms Swinson, who also served as a minister in the coalition government, will officially launch her campaign on Friday but is already the bookmakers' favourite.

The East Dunbartonshire MP confirmed her leadership bid on Thursday, saying: "I happen to think that this country is crying out for a liberal movement that will challenge the forces of nationalism and populism, and the Liberal Democrats need to be at the heart of that movement and I'm the person to lead it."

The party came second in the European elections and the YouGov poll for The Times suggested its popularity has increased even further.

The Lib Dems were on 24%, ahead of the Brexit Party on 22% and the Tories and Labour neck and neck on 19%.

It is the first time the Lib Dems have been in the top spot in a question on how people will vote in a general election since the heady days of Nick Clegg's popularity in 2010.

But YouGov's Chris Curtis cautioned against the Lib Dems getting too carried away with the bounce they have enjoyed since the European elections.

He said: "The Cleggmania of 2010 faded fast, with the party falling back in the final weeks of the campaign and ending up with just 1% more of the vote than they had won five years prior."

YouGov surveyed 1736 British adults on May 28-29.