A series of disaffected Labour and Conservative MPs could cross the floor and join the Lib Dems if the party makes big gains in the general election , Jo Swinson has claimed.
The Lib Dem leader teased the defections as she kicked off a nationwide tour with visits to three seats her party is hoping to rip from the grip of the Conservatives.
Eight MPs joined the party from Labour, the Conservatives and Change UK in the past few months.
Alongside Jane Dodds, who won the Brecon and Radnorshire by-election in August, it has seen Lib Dem ranks swell to 21.
They won just 12 seats in the 2017 general election.
Mr Swinson's decision to target the Tory marginals is a sign of the party’s growing confidence that it believes it can punish MPs from the Leave backing party in London and the South East.
But Ms Swinson said that a significant scale of defections was “entirely feasible” if the party defied expectations at the election, but would not be drawn on numbers.
She said: "In the circumstances where we don't reach a majority Lib Dem government our priority will still be stopping Brexit .
"I have also had MPs from both those parties saying to me that they think I would be a better prime minister than Jeremy Corbyn or Boris Johnson.
"Obviously, those people are standing under particular party banners.
"But it really is the case that those two old parties are fracturing.
“In the scenario that we do make this breakthrough then I wouldn’t assume that everything else remains static.”
Ms Swinson's tour, on an electric powered bus, took her to Golders Green and Finchley, where ex-Labour MP Luciana Berger is hoping to unseat Tory Mike Freer.
In 2017, Labour came second in the seat - but Lib Dem strategists believe that the anti-Semitism allegations against Mr Corbyn's party make them competitive in the seat.
But the first day of Ms Swinson's tour - which features a battle bus with a giant picture of her face - also took her to the seats of Watford and Esher and Walton, the seat of Foreign Secretary Dominic Raab.
Lib Dems are hoping that Remain voters will be sick of the hard-Brexiteer Mr Raab.
Asked if her party was being overly optimistic about the number of potential seats it could win, Ms Swinson was defiant.
“Politics is very volatile at the moment, and it’s volatile because we’ve got a new fault line that runs right through both the Conservative and Labour parties as they currently are,” she said.
“There are some people who hope, hope, hope it’s going to go back to business as usual, and that they’ll wake up from what they consider a nightmare and it’ll be the same politics.
"And I don’t think that’s going to be what happens.”
It came as the party said it would put a penny on every pound paid in income tax from April if won the election, with £11bn of the £35bn raised over the next Parliament ringfenced for mental health treatment.
Ms Swinson also unveiled the party’s priorities for the coming election - doubling down on a promise to cancel Brexit by revoking article 50.
The party claim that stopping Britain’s EU exit will unlock a £50 billion “Remain Bonus” that can be invested in public services.
Ms Swinson said: “Too many people – people who work hard and play by the rules – are struggling just to get by.
"Our country is crying out for a new kind of leadership and the Liberal Democrats are rising to this challenge.
"Our plan to build a brighter future starts with stopping Brexit, generating a £50 billion Remain Bonus that will benefit every part of the United Kingdom.”
The party’s other pledges included generating 80% of Britain’s electricity from renewables by 2030 and recruiting 20,000 more teachers.
The Liberal Democrats' five election pledges
1. Stop Brexit and invest the £50 billion Remain Bonus in public services and tackling inequality.
2. Tackle the climate emergency by generating 80% of our electricity from renewables by 2030 and insulating all low-income homes by 2025.
3. Give every child the best start in life by recruiting 20,000 more teachers as part of an extra £10 billion a year for schools.
4. Build a fairer economy by providing free childcare from 9 months and giving every adult £10,000 to spend on skills and training throughout their lives.
5. Transform our mental health services by treating mental health with the same urgency as physical health.
