Jo Swinson will make one final appeal to first-time voters on Wednesday, as the general election campaign enters its final day.
The Lib Dem leader will use a video message to say sorry to young people for how “ridiculous and so scary” the election has been.
Swinson has pivoted her campaign away from claiming she had a viable chance of becoming prime minister to urging voters to back the Lib Dems to deprive Boris Johnson of a majority.
And she will hammer home that message today with a call for young people to vote for her “unapologetically pro-Remain” party which will “choose a side” in any second referendum “not like Jeremy Corbyn who will sit on the sidelines”.
Corbyn has said he will remain neutral in any public vote if he becomes prime minister.
Swinson will say: “Congratulations. You get to vote in your first election. I’m just sorry that this election is so ridiculous and so scary.
“There’s never been so much abuse, extremism and division in our politics and how you vote will decide huge questions, like if the UK stays in the EU and even if our UK stays together.
“You won’t see another election quite like this one. Brexit is a national embarrassment and it’s already hurting our country.”
She will add: “There’s only one party that will stop Brexit and that can take lots of seats off the Tories. That’s us, the Liberal Democrats.”
Swinson, who has ruled out her MPs voting to put either Boris Johnson or Jeremy Corbyn into No.10, has seen the Lib Dem poll rating squeezed by Labour and the Tories as the campaign has gone on.
The YouGov MRP model released on Tuesday evening suggested the Conservatives would win 339 seats - a majority of 28.
The polling company analysed 105,000 voter interviews between December 4 and 10.
The result is down on the 68-seat majority that the same exercise predicted Johnson would end up with only two weeks ago.
YouGov said the surprise element of tactical voting and the tightening in the polls meant a hung parliament could not be ruled out.
According to the survey, the Lib Dems are on course to win in Richmond Park, St Albans and Winchester and are also likely to win back ex-leader Nick Clegg’s Sheffield Hallam seat.
Swinson will hold a series of rallies across target seats today including Esher and Walton, where the party also has hopes of ousting Foreign Secretary Dominic Raab.