Lib Dems should be challenging for government, says Jo Swinson as she rules out Labour or Tory coalition

Leadership contender rules out propping up a government led by Jeremy Corbyn or Boris Johnson, branding the Conservative frontrunner ‘unsuitable to be prime minister’

Liberal Democrat leadership contender Jo Swinson has said the party should be “challenging for government”, not simply aiming to hold the balance of power.

The volatile political climate meant it could no longer be assumed that Conservatives and Labour will remain the two biggest parties, she said, adding Lib Dems should have “no limits to our ambitions”.

In an interview with The Independent, Ms Swinson said it “beggars belief” that the Tories are contemplating installing Boris Johnson as leader, describing him as “unsuitable”.

She sees his likely appointment as an opportunity to win over centrist Conservatives who are horrified by his willingness to pursue a damaging no-deal Brexit. This, she said, would “make Black Wednesday look like a walk in the park”.

Speaking on the day that Johnson’s leadership rival Michael Gove admitted having used cocaine, the Lib Dem deputy leader revealed publicly for the first time that she had smoked cannabis while a student.

But she made clear she regards this as compatible with the long-standing Lib Dem policy of legalising the class B drug. She blasted the “hypocrisy” of Mr Gove forming part of a government which pursues a policy of criminalising consumers of softer drugs while himself having a history of using a class A substance.

She also admitted Lib Dems were “wrong” to vote to increase university tuition fees in England during the coalition with Tories, having made a manifesto pledge not to.

Ms Swinson, 39, is facing former energy secretary Ed Davey in the contest to replace Sir Vince Cable, with the new Lib Dem leader due to be announced on 23 July.

She said there was “more agreement on policy between us than you would find with the Tory contenders”. But said she believed her “non-tribal” approach to politics and ability to cut through to voters outside London and the southeast and young social media users gave her the edge.

“I’m the leader that can be the rallying point for the liberal movement that we need to create to take on the forces of nationalism and populism, the likes of Nigel Farage and Boris Johnson,” she said.

“The non-tribal way I do politics is perfect for this moment.”

Asked whether it was important for the Lib Dems to have their first female leader, she replied: “I think I’m the best person to lead the party regardless of my gender.”

Ms Swinson declined to discuss the possibility of individual pro-EU MPs switching to Lib Dem – such as Heidi Allen and Chuka Umunna, who last week quit Change UK, or Dominic Grieve, who faces possible deselection by his Conservative Association.

But she said: “I will continue to work with people where we agree. Our door is open to people who share our values and want to join the Liberal Democrats.”

The decision of senior Labour figures such as Alastair Campbell and Charles Clarke to vote Lib Dem in last month’s European elections was a “damning indictment” of Jeremy Corbyn’s handling of Brexit, she said.

“The only possible explanation for his stance on Brexit, when so many of his members and voters and his party conference are urging him to clearly back a People’s Vote, is that he is a Brexiteer and he wants Brexit to happen,” she said.

Ms Swinson said she would absolutely rule out propping up a minority government led by either Mr Johnson or Mr Corbyn, describing both as “Brexiteers hell-bent on a course of action that would be hugely damaging to our country”.

But she said that, with the party taking second place in the European elections, topping one recent national poll and recording its highest ever membership figure of 105,480, the Lib Dems should no longer be thinking about being the junior partners in a coalition.

“I have no limits to my ambition for the Liberal Democrats,” she said. “I think the fracturing of the two-party system that seems to be under way right now, we need to position ourselves as the liberal-minded people who want to see a positive progressive future for the country, where every individual can live with dignity and have opportunity, where we tackle our climate emergency and our economy is transformed to be able to focus on these priorities.

“I really think that that position can attract the millions of people across the country who are crying out for a positive alternative.”

She added: “I don’t think there should be any automaticity of assuming that the two parties that have until this point been the biggest will continue to be so. We should absolutely be challenging for government, not behaving as if holding the balance of power is the pinnacle of what we can possibly do.”

Jo Swinson brought her baby into the House of Commons chamber in a sling (PA)

The expected elevation of Mr Johnson, who had shown himself “unsuited for statesmanship” as foreign secretary “shows how far from the mainstream the Conservative Party has gone”, she said.

“We have got a Conservative Party that came fourth in a national election and is trying to pursue a course of action that would make Black Wednesday look like a walk in the park. We have got a contender for prime minister who has said ‘f*** business’.

“They certainly are trying hard to lose any shred of credibility that might have possibly remained. There will come a point – and that point is already coming – when the public turns round and says ‘We can’t possibly vote for that party’.”

Ms Swinson criticised the willingness of Tory leadership contender Dominic Raab to suspend parliament to push through a no-deal, calling it “a coup” that would trigger a “constitutional crisis”.

And responding to Michael Gove’s admission that he had used cocaine, she said: “It’s the hypocrisy of people like Michael Gove who have taken class A drugs and yet pursue policies on this ‘war on drugs’ which criminalise people, don’t offer help for people who have addictions and have been such a misguided way to address the issue and the problems caused by drugs in our society – that’s the thing that I find most troubling about this revelation.”

She added: “I smoked cannabis when I was at university. I think a lot of people did and do. I think our drugs policy doesn’t work and we should legalise cannabis. That’s been Liberal Democrat policy for a long time.”

Ms Swinson’s East Dunbartonshire constituency was one of 48 seats lost by Lib Dems in the bloodbath of the 2015 general election, when voter anger over tuition fees reduced them to a rump of eight MPs. She returned to parliament in the snap election of 2017.

She insisted the fee hike was “a good policy from a technical perspective” which had allowed more students from disadvantaged backgrounds to attend university. But she admitted: “We had pledged that was something we weren’t going to do and we did it. That was wrong and we shouldn’t have done it. We’ve been able to take some learning from that.”