At the time, he worked at TVNZ as the weatherman and asked MPs, queuing for a political show, for the local pronunciation of a place in Christchurch where he was warning of flooding. They all started arguing - no one could agree. It was an "oh my God" moment, says Mr Horan. "Up until that time I was keen to leave New Zealand in the hands of the politicians we had."
He read party policies and decided there wasn't anything that appealed or seemed as developed as what NZ First offered. He joined, ran for an East Coast seat in the 2008 election and worked for the board as a media adviser.
The party bombed, but Mr Horan was back in 2011, standing in Tauranga. By now, he was on the party board, deeply involved in planning the campaign. NZ First's vote in the city and surrounding areas were its best results in the country.
His mum Olwen was so proud, says Mrs Horan.
"She was beyond proud of him. Brendan was the golden boy. He achieved well, travelled overseas, had the TV career. He always used to take his mum to functions and she would sit up there [so proud]."
Mr Horan asked questions in Parliament, made strides with a KiwiRail campaign and learned the ropes. He also had an eye on taking over when Mr Peters retired, saying one of Mr Peters' closest advisers told him he would.
"I trusted when the time was right the leader of NZ First would pass the mantle over."
And then it all went wrong.
Mr Horan's mother died in August. In December 2012, questions were raised about spending from her bank accounts prior to her death. The executor of her will, nephew and second-hand-car dealer John Buckthought, said money couldn't be accounted for. A hand-written amendment to Olwen Horan's will also instructed him to get lawyers to recover any money loaned by or "taken" by Mr Horan or his sister.
Mr Peters put Mr Horan on gardening leave, and then asked for his phone records. The records would show Mr Horan had made 144 calls to the TAB line in 10 months.
Less than an hour after receiving the phone records, Mr Peters told Parliament Mr Horan was out of the party.
Mr Horan says the phone calls show nothing. "There were 144 calls in 10 months. Most of those days, I was lying with mum, on her bed, watching Trackside." If you ring on a landline, you go on hold, he says. He used his work phone - total cost $27.
"I grew up in racing. I've had shares in race horses. I have a TAB account. So what? So everyone who has a TAB account is an out-of-control gambler?"
The Horans were in Tauranga when he was dumped. Mr Horan's phone "exploded" with calls from media, Mrs Horan recalls. "I sat in bed and cried like a baby and never wanted to go outside again. Mum [Helen, Miranda's mother] was like, 'You've done nothing wrong. Get out there'. It was absolutely horrible."
Olwen Horan's money came from an Australian lottery draw more than a decade ago.
She returned to New Zealand with the remaining $720,000 of her winnings, buying a house for $400,000 and banking the rest.
As the family accounts and record keeper, Miranda Horan found herself working line-by-line through her mother-in-law's bank statements as accusations mounted against her husband.
"You can see every time her term deposit came up, she'd take between $10,000 and $20,000, put it in her spending jar and reinvest the rest. She was going through $25,000 to $30,000 a year in dribs and drabs. Add that up over 11 years, she'd spent a shitload of money.
"Good on her. It's her money. She was entitled to do that. It was hers. She didn't owe it to anyone. She wasn't a little old doddery lady, not until the last eight months of her life. She was stroppy. She did her own thing in her own time, doing as she damn well pleased and didn't ask anyone's permission to do it.
"People seem to think she won some money, then sat on the couch and waited for God to come and get her. Nana was a spendthrift. She loved shopping. She had all the best makeup. She had Yves St Laurent and all the makeups and perfumes You knew that she spent a lot of money."
Some of it went into the TAB.
Olwen Horan was an avid race follower. A fractured family, time together saw bonding over the track. "Some families hang out together and play Scrabble or go boating," says Mrs Horan. "They would all sit around and have their dollar each way, dollar here, dollar there. And it was about being right. It wasn't about gambling. It was about who was right."
The Weekend Herald has obtained documents showing Olwen Horan's will was changed three times a few months before she died, culminating in the final will that raised so many questions. The three changes were the first real changes since 2007 and included clauses which focused on Olwen Horan's other sons - sickness beneficiary Mana Orsmby and recently discharged bankrupt Peter Horan.
Mana Orsmby had a long-held belief that he was entitled to a share of his mother's winnings. A will of his from 2008, obtained by the Weekend Herald, stakes a claim on the winnings on the basis of helping buy the ticket when he lived with her.
"This is a family scrap about money," says Mrs Horan. "They figured out they weren't going to get their money because Nana had spent her money. So it had to be someone's fault. It's a family fricken' thing that's gone mental.
"I was gutted for [Brendan] when this happened. He doesn't deserve that." No doubt, she says, he leaves his socks lying around and sometimes leaves a mess. "That does my head in sometimes."
But not this. "He's a really good guy. He's a really good person."
Despite the pressure, Miranda Horan says she never asked her husband to quit politics. She harassed him, she says. "You're the one who wanted to go into politics," she recalls saying to him. "Good one - how's that working out for you?
"When it all blew up, I would have liked to have walked away. But at the same time, it was like an admission of guilt - 'we did do something wrong so we'll go away'. If you've done nothing wrong, you say, 'I've done nothing wrong - stick it up your bum'."
But when Mr Horan went off to work, she'd catch up with friends and wonder with them whether the pressure would ease if he quit.
"I would never expect him to do it. How would I feel if he wanted me to give up my dream? I'd resent him for the rest of my life."
The money doesn't make it worthwhile. There's the MP's salary of $140,000. "We made more money in business," she says. Politics is too hard on the family and too much work.
A year after Olwen Horan's death, the executor of her will reported on his investigation. "I have made inquiries and investigated all matters raised by family members and others. I can find no evidence which would enable me to found a claim against Mr Horan."
With an eye on the ongoing police investigation, Mr Horan says: "Part of me says, yeah, I'd love the police to charge Then I could say, yeah, let's go through this."
Occasionally, new allegations crop up. The couple suspect Mr Horan's former colleagues are peddling rumour. "Hell hath no fury like a Winston scorned," intones Mrs Horan.
When Mrs Horan mentions Mr Peters, her husband says: "It's not about that egg. Don't even mention his name." And throughout the interview, he doesn't, preferring to call Mr Peters "the leader of NZ First".
"I don't really care. Less than 95 per cent of New Zealanders care about NZ First.
"When it comes down to it, I can put up my record. I can show the legislation I've passed. I can show the ministers I've worked with. NZ First can't because they haven't done anything."
For Mr Horan, it's been a long slog trying to get back to where he wanted to be when he first entered Parliament almost three years ago. He says he was ostracised, but now claims acceptance from many on the basis of the work he does.
The "Mondayisation" bill, giving public-holiday Mondays when statutory days fall on weekends, passed with his vote. He says he has worked with ministers to insert clauses in legislation, and met with ministers to further other causes.
"I believe I've earned their respect. I've worked with a lot of National ministers. I'm coming from a space of genuine respectability."
And he's going at it again this year. Mr Horan has created the New Zealand Independent Coalition. The party's catchcry is a set of binding principles guided by polling of the electorates throughout the three-year term to guide its successful MPs. Simply, Mr Horan believes party politics have isolated politicians from the people and the NZIC will return power to the electorate.
The oppositional Westminster system of Parliament has failed, he says. "It's just parties taking stances and defending their viewpoint, and the people of NZ are the casualties.
"It's a great challenge. I will give it what I give everything. I will give it 100 per cent. If that's not good enough on the day, so be it. I'll go fishing."
