Curtains are twitching in a small town where an unusual trio have become unlikely minor celebrities in the General Election.

At first glance there’s nothing peculiar about the three women in bright yellow out on the campaign trail.

But the Lib Dem threesome are more than just canvassing buddies and they’re aiming to make a bit of political history into the bargain.

Parliamentary candidate Zoe O’Connell, 37, is bidding to be Britain’s first polyamorous MP – which means she lives in a three-way lesbian relationship with her two canvassers Sarah Brown, 41, and Sylvia Knight, 39.

And if that seems to be as far fetched as a Tory manifesto, then consider this: Zoe and Sarah used to be MEN. And Sarah and Sylvia were once a straight married couple before her sex change.

So it’s no wonder the trio – nicknamed “the leaflet delivery cult” by locals – have got tongues wagging in their constituency in the run-up to polling day.

But that doesn’t bother Westminster hopeful Zoe. In fact the complex personal life and happiness of her and her lovers is at the forefront of her campaign.

She says: “We’re content together and that is what matters to us. I’m running for office to change things. Twenty years ago this would never have happened.

“I’m standing up because I don’t think anyone should be treated differently because of gender or sexuality or the way they choose to live their private lives. We live together.

“We’re in a relationship and we’re not ashamed of that.”

But they’ve all been on a long and difficult journey to reach their unorthodox domestic bliss.

Zoe was a male IT worker and dad of three when she split from her wife in 2005.

Nagging doubts about her sexuality that plagued her in childhood resurfaced – and as divorce proceedings gathered pace she suddenly realised she was a woman trapped in a man’s body.

She says: “For some people it’s a gradual realisation, but for me it was a light bulb moment. I know the exact day I figured it out: October 13, 2005.”

Computer network engineer Zoe had started talking to a transgender woman in an online chatroom.

It set in motion a series of events that led to the creation of her very modern relationship.

Zoe O'Connell
Would-be MP: Zoe O'Connell is standing for the liberal Democrats in Maldon Essex 

She says: “At the time I likened it to some kind of bomb going off in my head. You suddenly have a big burning issue that you have to deal with there and then.

"I’d known since forever that something wasn’t right.

“I wasn’t sitting around playing with Barbie dolls at the age of five, but there was something wrong. I just thought everyone thought in those ways, and it was perfectly normal.”

In December 2005, Zoe – who had decided to transgender – met married fellow transsexual Sarah online.

Zoe had posted a question about hair removal on a LiveJournal forum shortly after Sarah began her own transition with the blessing of her wife, Sylvia.

Sarah says: “I asked if Zoe wanted to get together for a cup of tea. We met and became friends.

“It took some time before we realised we had feelings for each other. Zoe was married at the time and going through a divorce.

“She had had a couple of relationships with other people and we were only friends. But we were going through the same thing, speaking to the same people and comparing experiences.

“We were giving each other mutual support. It was all very platonic for about a year and a half and we were each there when the other went through surgery.”

Their shared experiences only helped to intensify the relationship, and by 2008 they both worried the budding romance could plunge Sarah’s relationship with Sylvia into jeopardy.

The two had been forced to divorce after Sarah’s transition because the law then prevented marriage between two women.

But they were still in love and living as a couple.

Sarah, 41, says: “Infidelity wasn’t on the cards for me. But Zoe and I knew it was something that needed to be dealt with, because it was getting awkward.

“So we sat down and basically thrashed out exactly where things were and what was happening.”

Sarah was worried how Citizens Advice Bureau volunteer Sylvia, 39, would react.

But she plucked up the courage to tell her about Zoe and was amazed when her former wife said she welcomed the idea of living together in a three-way relationship.

After overcoming some initial teething problems, like the correct way to hang toilet paper, their relationship – described as a “triangle” of equal partners by Zoe – has gone from strength to strength.

For the past seven years, the women who live in a three-bedroom home in Cambridge have shared everything, from support for the Liberal Democrats to a vast collection of old cameras, several pet snakes, and a love of climbing and sailing.

Zoe O'Connell
Close: Zoe O'Connell, transgender Lib Dem candidate, and her two friends, Sarah Brown and Sylvia Knight 

The sleeping arrangements have changed over the years, but more for reasons of comfort than a dimming flame of passion.

Sarah, a former microprocessor technician, says transparency and brutal honesty has underpinned the unusual relationship.

“We tried sharing one room, but had to be honest in the end that three people in one bed doesn’t work very well.

“The middle person doesn’t get a lot of sleep,” she says.

“The situation currently is, I mostly sleep with Sylvia, and Zoe mostly sleeps by herself. That’s basically down to individual preference and comfort.”

Zoe was bridesmaid when Sarah and Sylvia took their vows for a second time in a civil partnership six years ago.

She says: “It just works. There’s more often someone there to be supportive.

“If one person’s off doing something else then the other partner is still there, and you can just keep each other company. It’s given me strength since I underwent my transition.”

Zoe says her relationship with her children – an 11-year-old boy and two girls, 13 and 14 – is “no different” to what it would be if she was still a divorced father.

She spends weekends with the children near the old family home where she grew up in Burnham-on-Crouch, Essex, but instead of “Dad” they simply call her “Zoe”.

Sarah Brown
Campaigner: Sarah Brown 

“The kids were three, four and five when we separated,” she says.

“They were quite young, and it was a lot easier for them that way.

“Over the course of about four to six months I was spending more and more time in ‘girl mode’, which seems like a very strange thing to say now.

“They kind of gradually got used to it. There wasn’t much in the way of verbal explanation.

“Since then I think they’ve just absorbed information via osmosis.

“They hear the conversations happening around them every day and have picked it up, because it’s normal for them.”

Even though they’ve been the victims of cruel playground jibes, Zoe has no regrets over her three-way relationship.

She says: “It’s been difficult knowing that they’re on the receiving end of it all, but I don’t think children in the playground think that I’ve put them in this position.

“They just see a way of getting at someone and they use that. They push that button. And the buttons are different for each child.”

Zoe is more concerned that increased attention will be levelled at them on a national scale if she becomes an MP.

Zoe O'Connell
Campaigning: Liberal Party canidate Zoe O'Connell at home with her two partners Sarah Brown and Sylvia Knight 

She says it is “inevitable” that she will become a flagbearer for gay and transgender issues if elected, and will fight to have them included in any equalities legislation that is passed during the next parliament.

She says she and Sarah, who was a Lib Demcouncillor in Cambridge until last year, have been welcomed into the fold by politicians.

But while Zoe likes to think the best of everybody, Sarah says she fears national politics will expose her partner to abuse from bigots online.

“There are people who will go for you if you’re transgender and you stick your head above the parapet,” says Sarah. “They’re not very nice people.

“The ones doing it have got form, and I’ve seen them doing it to other people. They know about Zoe, and I imagine she’s probably on their hit list.”

But Zoe, who is contesting her family home constituency of Maldon, Essex, against sitting Tory MP John Whittingdale – certainly isn’t frightened of how people react to their relationship.

She says: “There are all sorts of issues there, but I think nothing of giving Sarah or Sylvia a kiss goodbye outside work or after we meet for lunch. It’s not an issue.”

Three other candidates are also vying to become the first transgender member of the Commons next month.