In politics we vote for insiders but secretly yearn for outsiders. In the American elections the candidates accuse each other of being part of the establishment as though that were a slur. Faced with the sameness of our own candidates we enviously eye the theatrics and colourful contrasts of their primaries. And on both sides of the Atlantic election fatigue is signalled by the old complaint: "They are all the same."

You would hardly think, in trying to satisfy this craving for freshness, to look North. And yet it is here that we find the candidate who is incontrovertibly the 2016 election season's most compelling outsider. Her youth - she is just 22-years-old - and gender would already set her apart on Stormont's homogeneously grey benches. But at a time when the North is casting itself as a final bulwark against encroaching LGBT rights, Ellen is also openly transgender. At a moment when economic recovery is still the primary electoral obsession, she is a self-confessed "insufferable hippy". In a profession where effective communication and high emotional intelligence are all but job requirements, she suffers from Asperger's. In short, you could not get a more unlikely politician.

And yet, in some ways, she also feels like a hand from history. With many of the gay rights battles all but won, transgender rights seem like the next frontier of social progress. There is a sense, perhaps, that with the bleak prospects and tough start that most young people have had over the last few years, it has become all the more important that more of them have a ­political voice. And with the stigma around ­social difference rapidly receding, how curiously apt that now someone who is open about having an autism spectrum disorder would present themselves to the electorate.

Of course it is the transgender facet of Ellen's story more than anything that has made the world take notice. On the afternoon we meet she has already dealt with the BBC and Al Jazeera. Her diary has become crammed with speaking engagements and advocacy work. Her selection has been called "a major step" for the province.

The journey to meet Ellen is a reminder of how Belfast exists on the faultline of social progress. Graffiti scrawled on an underpass on the way into the city read 'Taigs will be dealt with'. The increased frequency of murals warns you that you might have wandered too far in one direction. Over the student union, the rainbow flag flutters defiantly.

Ellen herself arrives on a motorised bike. She stiffens up at an attempted peck on the cheek. Even in person she is not quite what you expect. Perpetual media bombardment of images of Caitlyn Jenner might have beaten one into the belief that the end point of male-to-female transition is vampish, larger-than-life womanhood. Something a little Jessica Rabbit around the edges. But Ellen is defiantly mousey. And yet somehow the lack of cosmetic distraction makes her seem even more perfectly female.

She was "a ceasefire baby", born just before the IRA downed arms, in 1993. "I grew up in the Falls Road, West Belfast, in a very homogeneous community - working class nationalist," she tells me between sips of tea. "My parents were both teachers. It was a happy childhood but The Troubles were there, a part of life. A couple hundred metres from our house was one of the peace walls. There were armoured cars. When we went to see family in Fermanagh we had to go through army checkpoints. I saw bomb scares. At one point we got three weeks off school because there was an unexploded old bomb from the Second World War."

Of course, in those years Ellen had another name. But she does not care to say what this is, and asking it, as I do, seems like a type of violation. Even for someone as professionally nosy as me there are some questions that feel taboo. Orange Is The New Black transgender star Laverne Cox firmly drew the line for Katie Couric when the journalist asked her how far she had gone in terms of gender reassignment surgery. "Crying Game or all the way?" does not feel like fair game, even if the question invariably intrudes on the highest of minds. Ellen is patient with me. She knows, perhaps, that we understand things primarily in physical terms. If we did not, the surgery itself would hardly be necessary.

But in our rush to inspect this brave new world we must also understand politeness. And for many transgender people this question is impolite. Ellen never gives the impression of trying to cynically weave a campaign out of her own personal narrative. She imparts information matter-of-factly. This seems to entitle her to draw boundaries.

Also she's just a bit shy - another novelty in this era of self promotion.

"I grew up in my own world," she tells me. "I didn't really bother with having human friends. I spent a lot of my childhood drawing street lights in chalk on the backyard. I had very particular interests: I was always fascinated by roads and road design, infrastructure and urban design."

Ellen says that she was "blissfully ignorant" that anything was wrong until she was around 11 or 12 and attending an all-boys school. "From birth, we're constantly assured that we'll grow up to love someone of the opposite sex, and that we'll get married and have children, and if the marriage lasts, we'll grow old together. We're taught that boys will grow up to be men and girls to be women, and that no-one really questions that."

Ellen suspected that puberty was going to be awful "because everyone said that it would be, but you have no frame of reference except to realise that you can't discuss boys around classmates. I intuitively understood that something was different."

This manifested itself as what she calls "a stunning sense of confusion and dissociation between myself and my body, (which) made me feel like I was totally broken." At times, she tells me later, she felt suicidal.

Once she had the language to describe what exactly her feelings were, her transgender identity began to manifest itself as a more urgent thing. "The internet gave me people to connect with, but away from the keyboard it was more difficult. I wouldn't say I particularly identified with women in the family. I was, I would say, a little scared of the issues that would come to the surface."

Ellen first told her GP about her ­transgender feelings. "I told everyone else in a burst of about two or three days. For friends and family it was a surprise. People just need guidance. I still looked the same." For those close to her, she laid out what she wanted in terms of being called Ellen. "I was lucky in that my family and friends were very supportive. My family needed some support themselves but they wanted to be supportive to me. There were a couple of individuals who couldn't support me but there was no nastiness or deliberate hurting of me and that seems to be quite unusual."

She went to college to study electrical engineering - which she describes as a hobby - and began transitioning socially while waiting for medical referrals in Belfast. Hormone replacement therapy was part of the "long, slow-but-steady journey towards changing my biology towards something more comfortable and much more bearable".

Her entire treatment happened through the NHS but progress was slow. "I would be told you can expect to be seen at no time in the foreseeable future. That was what got me involved in political advocacy. My case was brought up in the Assembly." She also came up against certain prejudices in the services she accessed. "You are allowed to be gay, for instance, and you are allowed to be butch. But there is still the idea that someone can 'not quite be trans enough'. And there are certain guidelines that they expect you to follow. You are expected, for instance, to be out to everyone and to transition in what they call a gender-appropriate fashion."

In September of last year she had her "major surgery". On Twitter she displayed her characteristic wryness about the event: 'Especially enjoyed the whole surgery being a "drastic step" like it's some sort of natural disaster documentary.' She describes the full process of transitioning as ongoing.

Was she daunted or frightened by any aspect of the surgery and medical procedures? "No, I welcomed all of that. I was anxious and there is a level of culture shock. I was definitely perceived immediately by everyone as trans and if I did encounter any opposition it tended to just come in the form of plain old sexism, which seemed like the lesser of two evils. I've noticed since transitioning that people treat me far less seriously. People also tend to take trans people much less seriously and you do experience a level of street harassment. There have been a couple of incidents of physical harassment."

She doesn't agree with the current situation in the UK and Ireland in which the gatekeepers for state-funded medical interventions and hormone therapy are psychiatrists and therapists. "Some trans people may need mental health support but I think it's very important that we understand that being transgender is not in and of itself a mental health problem. Lack of access to services can, however, in some cases, constitute a risk to mental health. Most trans people I know would say that they wished that they had been able to transition earlier than they did."

In tandem with working her way through her gender reassignment process Ellen has also learned to manage her Asperger's. "I knew I was different in that respect too during my teens. I was very sensitive to sensory stuff and had trouble hearing people where there was background noise - I would lip-read a lot of the time. I noticed I would get quite obsessive about things - my interests - far beyond the level of detail that other people would get into. I also had social issues around understanding people's emotions and intent. For someone with Asperger's it's a lot of effort to interpret non-verbal communication." She became involved with self-help groups, which she calls "affirming and cathartic". She has learned coping mechanisms and has made huge progress. "Even a year-and-a-half ago I wouldn't have been able to do something like this interview. Of course there are some very daunting aspects about politics - it is a very brash, loud field of work. But I don't think that's a reason to not get involved. Politics needs to become more accessible to people with disabilities. I don't think it's going to be a stumbling block for me, but it will be a difficulty."

Ellen is in a relationship at the moment but remains deliberately opaque about the gender of her partner. "Him, her - I think that's very binary. I met 'them', let's say, in various ways at Queen's and through the LGBT society. I was very open about my journey - they are also trans themselves." Ellen says she has never wanted kids but she may, in the future, be open to adoption.

For the moment she gets the majority of her joy and satisfaction from her work. She has founded and is the current chairperson of GenderJam NI, an advocacy group for transgender youth, and has been campaigning since April 2013 for better access for transgender healthcare provisions in Northern Ireland. She's also a consultant on trans youth issues to several public and statutory sector bodies. And the push is on to get her elected as a Green Party representative in West Belfast. "Almost two decades after the Good Friday Agreement, West Belfast is still one of the most deprived and disadvantaged areas in Western Europe, in part due to the wasteful zero-sum politics at Stormont."

She says that her odyssey of self-determination has made her all the more eager to fight on behalf of those who don't have a voice. "A few years ago I wouldn't have had the confidence to do any of this, but now I have that. Northern Ireland has not been a friendly place for the poor, the marginalised, and especially LGBT people. I've been very lucky in some ways and I've come a long way myself. Now it's time for me to stand up for other people."

Visit www.ellenmurray.co.uk

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