Former political director with the Irish Yes Equality campaign Tiernan Brady has been in Sydney for the past 20 months, running Australians For Equality, based on the successful Irish model. After Australia voted 61.6 per cent yes in a postal survey about changing the law to allow same-sex couples to marry, Brady took time out from the celebrations on Wednesday to tell Irish Times Abroad about reaction to the result.

I was in Sydney this morning with about 20,000 people in Prince Alfred Park, as the result of the marriage equality survey was called out at 10am on the dot. There were similar gatherings right around the country.

Australia is made up of five states and two territories, and all of them voted yes. Of the parliamentary constituencies, 90 per cent voted yes, and of the people, just under 62 per cent voted yes. Australia didn’t say yes, Australia roared yes.

Celebrations kick off at the State Library of Victoria in Melbourne. Photograph: Scott Barbour/Getty Images

It is every bit as magical as the Irish referendum result in 2015. The feeling in Dublin Castle that day was undistilled joy. We saw that again today. This is a giant country, telling a group of people who were never really sure they were full members of society, you are in. We see you. All you wanted is to be treated the same as us, and when you asked us we said yes. The feeling of empowerment and belonging that grows from that is phenomenal, and it is being felt all around the country today, from the Indian Ocean in Perth to the Pacific Ocean in Brisbane.

I have been here 20 months now, and when I arrived there was no official organisation. There were some very good voluntary groups, but they knew they were facing a public vote in a country with 25 million people bigger than Europe. We had to build the campaign from scratch, bring in the best people from all perspectives of life who would engage with the different faith communities, different ethnic communities, and to get past the challenge of the sheer scale of Australia.

I think Australia should give @Tiernanbrady honorary citizenship, make him a Dame, and give him a kangaroo or a billabong or whatever. He did an amazing job as Director of @AMEquality. He’ll probably never come home now though. #MarriageEquality — Dr Panti Bliss (@PantiBliss) November 14, 2017

Supporters of same-sex marriage celebrate the victory. Photograph: Danny Casey/EPA

It is not like Ireland where you can get on a campaign bus and drive around. We had to build a campaign that empowered people to understand that the bus could not coming to Alice Springs, so people themselves have to be the campaign by standing up and telling their story, by going and knocking on doors. That was the biggest challenge compared to Ireland.

I was confident that yes would prevail. The biggest perk of my job was getting to travel around Australia, and the more I travelled the more I realised how Irish it is. This is a country with the same values, a country that believes in fairness and equality. The Australian people like to say this is the “land of the fair go”, but the more I travelled the more I realised that wasn’t just lip service. That value is deeply entrenched.

Celebrations at Prince Regent Park in Sydney. Photograph: David Moir/EPA

As long as we ran a campaign that stayed positive, that focused on human stories, people were going to vote for us. You can never be 100 per cent sure, but I was as confident as I could be that the Australian people got what this was about, and would vote yes.

I am confident the legislation will pass in December. If the government was going to spend $150 million on a public vote that wasn’t legally required, there is no way they can ignore the result. As we saw in Ireland, the momentum that comes from a public vote of endorsement will sweep all before it. I expect this bill will be introduced in the senate in Canberra on Thursday morning, and there is no reason it won’t be passed before Christmas.

We have a huge mobilisation job to do over the next three weeks. We have to make sure the message is clear: the people have spoken, and now it is time for the politicians in Canberra to do their job.

As for me, I missed Christmas in Ireland last year, and anyone with an Irish mother knows you can’t get away with two in a row. So I will be home the first week in December for a few weeks, but I will be coming back to Sydney. My partner is here now, so we will sit down in January and have a think about what we do next. Only two countries in the world have done this, and it has been a joy to be stuck in the middle of both of those campaigns.

- In conversation with Ciara Kenny