“You cannot run for Mayor of London seriously and say that Brexit is not a London issue.” Siobhan Benita will fight the London mayoral election in May next year – more than three months after Britain is due to leave the European Union. But Brexit is central to her platform.

The Liberal Democrat candidate has been here before. In 2012, Ms Benita ran for Mayor as an independent, winning more than 80,000 first preference votes, and finishing fifth. “Why wouldn’t you want to be Mayor of London”, she asks. “I think it is one of the best jobs you could do in politics, because if you get it right you can make so many people’s lives that much better.”

We’ve created such a toxic environment because of Brexit and we’re fighting against that as well

The passion for London remains – but this time, things are different. Ms Benita joined the Liberal Democrats in the wake of the European Union referendum. One of her two daughters, she admits, was a member several years before.

For her, Brexit is about more than an in or out vote. “It’s about our inclusivity,” she explains. “What we’re seeing at the moment is the rise of hate crime. We can’t allow that to happen on the streets of London. We’ve created such a toxic environment because of Brexit and we’re fighting against that as well.”

But with a General Election just round the corner, Ms Benita is feeling good. Going into the campaign, the Liberal Democrats had four MPs in London – but this time round they’re hoping for as many as 15, she tells me.

Enfield Independent:

Benita canvassing with former Labour MP Chuka Umunna.

The party is riding the golden wave of the European elections. The Liberal Democrats took 20 per cent of the vote in London – more than any other party – and sent three MEPs to Brussels from the capital.

Now they’re pushing for Westminster wins, with big names on London ballot papers. Former Labour MPs Chuka Umunna and Luciana Berger are standing in the City and in Finchley. Former Conservative minister Sam Gyimah is challenging the Kensington seat. And the party has its sights set on Streatham, Putney and Wimbledon as well.

In the push for the General Election, it’s easy to lose sight of the mayoral race – but Ms Benita is positive. “All of that is good for me,” she says. “All of that builds an even stronger foundation for me going into the mayoral elections.”

We then become the rallying cry in London – for everybody who feels Brexit has been a mess

She’ll need a strong base if the latest polling is right – almost half of Londoners plan to re-elect Sadiq Khan next year, with Conservative candidate Shaun Bailey and independent Rory Stewart both polling ahead of Ms Benita in the latest YouGov survey.

Success in the European elections hasn’t yet translated into a Liberal Democrat surge in the mayoral vote. Will Londoners still choose on Leave and Remain lines if Brexit has already happened?

Ms Benita thinks they will. “We then become the rallying cry in London – for everybody who feels this has been a mess and everybody who wants to fight it,” she explains. “It won’t be over. It’ll just be the start of the next phase.”

Enfield Independent:

Benita ran for Mayor of London as an independent candidate in 2012.

Multicultural, diverse London is woven into Ms Benita’s policies, and into her own identity. Her mum is from India, her dad from Cornwall, and her husband from France. She now lives in New Malden, in Kingston – just five minutes from her mum’s first flat in London, where she lived as a child after emigrating to the UK.

The butcher’s shop her mother lived above is still there, and Ms Benita fondly remembers stories of the shopkeeper bringing the family cuts of meat, and the milkman giving them bread – the kindness of strangers in a new place. “That’s definitely still the London that I think we have,” she says. “I still think London is the most welcoming, inclusive city on earth.”

London might be that city. But today, it faces its own challenges, above and beyond the potential fallout of Brexit: air pollution, the cost of housing, and most starkly violent crime.

At the heart of the public health approach is putting police officers back in the community

Ms Benita is a member of the Youth Violence Commission, a panel of MPs and experts set up to scrutinise the rise in attacks on young people nationally. The commission’s interim report, published last summer, backs a public health approach to violence – so it’s little surprise that Ms Benita’s policies chime with Sadiq Khan’s.

But the Liberal Democrat candidate worries that “warm words and good intentions” from the Mayor are not translating into real change. She wants something more transformative and more radical for London. Her most eye-catching policy is the decriminalisation and eventual legalisation of cannabis. It’s something the Mayor has also now hinted his support for – but will Londoners go for it?

Ms Benita has never smoked cannabis herself – she once tried a cigarette, but says drugs aren’t her thing. Yet she admits she has “some sympathy” for the blanket decriminalisation of drugs, treating substance abuse as a health issue rather than a crime. Her concern is convincing voters.

“I’ve always had this thing of can I take the Fulham mum on this journey with me”, she says. “I think you have to start with legalising cannabis and regulating it. It’s too much to expect that further step.”

Enfield Independent:

Benita is campaigning to stop Brexit.

Beyond the headline, Ms Benita’s crime policies focus on young people. She wants to end permanent exclusions from London’s state schools, provide more after school activities, and appoint a Young Mayor to ensure children’s voices are heard.

On policing, she believes quality is just as important as quantity. “At the heart of the public health approach is putting police officers back in the community so they’re seen as a positive service, not a force,” she explains. “I would reopen police stations across London – and if you can’t reopen them in the old buildings that are costing too much money, reopen them in your post office or in a community centre.”

Crime and policing will be among the defining issues of next year’s election – but the Mayor’s powers have limits. And while Mr Khan’s calls for devolution to London are seen by some as a party-political attack on Conservative governments, there are restrictions to the role, not just in tackling crime but across the board.

But Ms Benita is undaunted. “If you’re Mayor of London and the only thing you’re going to do is say, I can’t do x-y-and-z because I don’t have the direct power, that’s just ridiculous,” she says. “Any politician will tell you – or maybe any female politician will tell you – that to get things done it’s all about relationship building. It’s all about good communication and soft power.”

I thought, actually if women like me don’t walk the walk and not just talk the talk then nothing’s going to change.

If elected, Ms Benita would be London’s first female Mayor. She’s very aware of that stark absence – indeed, it was partly behind her move into politics. “My motivation in 2012 was about my daughters,” she explains. “The three parties had the same three white men, the same candidates who had stood in the 2008 election. Politics was already starting to get a bit dysfunctional and broken: it was the start of the parties going to extremes and I thought, actually if women like me don’t walk the walk and not just talk the talk then nothing’s going to change.”

Even second time round, Ms Benita doesn’t think of herself as a politician – “it’s all still new to me, especially party politics”. And though Brexit looms large, at its core her motivation remain the same. “I don’t think there is any city that is as good as London for its inclusivity and its quirkiness and its innovation,” she tells me.

“But I also know that for a lot of people, London is a difficult city to live in. All of those things I love about London and all of its amazing opportunities aren’t accessible to everybody – and that should change.”