Rain is mercilessly pelting Westminster but Jo Swinson – the woman who could soon lead the Liberal Democrats – strides into the building full of sun. Sporting a flower-print beanie hat and a wide grin, the 39-year-old mum has good reason for the spring in her step.

Last week her party emerged as the big success story of the local elections – snatching control of ten councils and winning some 704 new seats. Hopes are now high they can capitalise on their pro-Remain position in the forthcoming European elections. 

Because after a punishing few years in the wake of the David Cameron-Nick Clegg coalition government, the Lib Dems have managed to capitalise on their pro-European credentials and appear to have finally beaten a path out of electoral wilderness.

Swinson hails the Lib Dems’ heritage of “good local campaigning” for the upswing, but recognises the tough road ahead as her party competes for the pro-Remain vote with the Green Party, Plaid Cymru, the SNP and new kid on the block Change UK.

“We have a saying in the party – ‘where we work, we win’ – and now that maxim holds true again,” she says, celebrating what she describes as “astonishing” wins in Chelmsford and Winchester. 

There had initially been hope of a pro-remain alliance, but it didn’t take long for them to be scuppered after Change UK declared it would stand a full slate of candidates. But now, following a series of embarrassing setbacks (including several logo changes), the new party is struggling to make headway –  and Swinson cannot resist a little swipe.  

“When you compare the existing infrastructure of the Liberal Democrats to that of Change UK, we are in luxury by comparison,” she says, pointing out that her party has in excess of 100,000 members and 2,500 councillors.  

“You look at a party that has got hardly any staff or history or institutional memory of these things, and of course it is hard for them.” 

The East Dunbartonshire MP is widely regarded as the frontrunner to succeed Sir Vince Cable, who took the reins when Tim Farron stepped down in 2017. Though she has not yet declared her candidacy, preferring to keep the party “united” for the poll, it seems a sure bet.

“I have lots of ideas about what should happen in the party,” she says. “So it is a watch this space answer for now.” 

Swinson has a long history with the party and has put herself at the centre of core campaigns, including opposition to the Iraq war, Labour’s proposals for identity cards, and votes at 16. 

Her election would see the party have a female leader for the first time ever. 

But some members hoping for a fresh start may view her close association with the coalition years, as a parliamentary private secretary for Cable and later Nick Clegg, as potentially damaging the party. 

But the party’s role in the coalition is a source of pride, not shame, for Swinson. “There were big highs and there were big lows but ultimately what you are able to achieve in government is huge,” she says. 

“They say ‘your worst day in government is better than your best day in opposition’ and there is definitely a lot of truth in that.” 

She adds: “You can really change things through using that ministerial power. I feel like on shared parental leave, on gender pay gap reporting, on the groceries co-adjudicator on the suppliers of supermarket not being ripped off. I look back on that time in terms of what I was actually able to do, it was huge in terms of improving people’s lives. 

“Obviously there were some compromises that came as part of that and we didn’t get every decision right and we all learned a lot.” 

Those learnings might come in handy very soon. Poll after poll suggest that in the event of a snap general election – which looks inevitable given the looming Tory leadership contest – we could be facing another hung parliament. 

The Lib Dems could once again be in the position of kingmaker and Swinson refuses to rule out a future coalition. “The way I come at it is that, as party that supports proportional representation, I believe in pluralism,” she says. “I actually think that having a range of views around the table you get better decisions and that is a better, more mature way to conduct politics.

“I think a pluralist way is the best way to approach it and that means working with other parties, so, yes I think in principle, it would be strange for the Liberal Democrats to rule out that idea.” 

As well as a coalition with the Tories, the Lib Dems have shared power with Labour in Scotland and Wales. 

But if either party continues to push for Brexit without committing to a second referendum, Swinson says any such deal would be off. 

“I think the difficulty, in looking at the current Conservative or Labour parties, is that these are parties that are being led to ideological extremes and pursuing a policy which is damaging to our economy and which we are fundamentally opposed to – Brexit – that it is hard to envisage in the current environment, but in principle, absolutely, [a coalition] is the type of politics we ought to support,” she says. “We are in politics to make a difference and being in government is part of that.” 

It also seems unlikely a Liberal Democrat party led by Swinson would be comfortable working with a Boris Johnson-led Tory Party. 

“I think the Conservative Party is in a terrible state if that is who they pick to be leader. He is not fit for that role,” she says, adding: “If Boris Johnson were a woman, his political career would be over. The double standard is bizarre.”  

She slates the “pure personal ambition” that led Johnson to back Brexit, adding: “He is the exact opposite of a statesman. 

“There are people who campaigned for Brexit who had long held that position and I can respect that even if I disagree with it.” 

The Brexit Party, led by Nigel Farage, would also be unlikely to win their backing. 

“I will never forget the morning after the referendum, Nigel Farage surrounded by men – and it would be men – and him saying we won the referendum without a shot being fired,” she says, pointing out Labour MP Jo Cox had been murdered just days earlier by a far-right terrorist. 

“I just wanted to vomit. I just felt so sick.” 

‘I always wanted to change the world. It sounds twee but it’s true’

Swinson’s journey into politics seemed obvious from an early age, with a role on the school council in her Glasgow state school. 

“I always wanted to change the world. It sounds twee but it’s true,” she says.  

Her first campaign was to get the teachers to allow girls to wear trousers as part of their uniform. “Incidentally, I didn’t want to wear trousers,” she says. “I just thought it was in principle wrong. I was very happy wearing a mini-skirt.” 

Growing up, she was inspired by Body Shop founder Anita Roddick, who pioneered ethical consumerism in the 1980s.  

“The Body Shop was part of life then,” she says. “You would go and pick up your Christmas presents and those soaps in the shape of different fruit, then you would get to the till and there would be some sort of petition or a campaign card about fair trade or community empowerment or animal testing. 

“I really loved that campaigning approach.” 

Swinson, the daughter of a teacher and a town planner, joined the Lib Dems age 17 at a freshers fair at the London School of Economics, where she went on to study business management. 

After graduating with a first-class degree, she worked in public relations for a radio station in Yorkshire and it was then that Swinson took her first tilt at Westminster. 

She contested Hull East in 2001, held by the then deputy prime minister John Prescott. 

“I was 21 and he was 63. You know I never saw him, which tells you a lot about Labour at that time,” she says. 

After winning her Scottish seat in 2005, Swinson was the youngest MP or ‘baby of the House’. 

“I was aware of Westminster being more ageist than sexist,” she says. “Because I was the youngest MP, people made a lot of assumptions about what I could understand. 

“Perhaps that was a combination of ageism and sexism and I wonder if they would have behaved that way were I a young man. 

“With hindsight, I don’t think it was the type of sexism that said ‘you can’t do this’ but with politics, the structures are quite informal in terms of where power lies in parties.” 

Swinson, who during the coalition was minister for women and equalities, has established herself as a leading equality campaigner. 

She made headlines last year when she became the first to take her baby into a Commons debate about proxy voting. 

She hopes parliament is undergoing a process of modernisation but says the informal set-up of political parties means women are often “just completely forgotten about”. 

Female colleagues of hers during the caalition years were overlooked for promotion, she says.  

“You might think ‘well, that’s just how it happens’ but on so many occasions it is the case that the woman is thought about last, because the blokes got together in a room and ‘worked it out’ and decided what needed to be argued for,” she says. 

Asked what good leadership means, she replies: “I think it’s about being authentic, being clear about where you want to go and being inclusive.”  

While climate change will be a central plank of Lib Dem policy, stopping Brexit is the first order of business for the party, she says. 

“The quickest way to make this stop is to have a referendum and to vote remain – any other option is at least a decade of negotiations like this, and who wants this to go on for another decade,” she says.  

“We have a big chunk of the population who just want this to stop, this constant constitutional wrangling which is tiring for people.”

Should the Lib Dems succeed in securing a second Brexit referendum, the Remain case should not rely on how leaving the EU will hit the economy. “We need to be much, much better at making the emotional case for being part of the European Union,” she says. 

“It came out of a continent that was ravaged by war twice in one century. It was a project to say ‘this cannot happen again’.”