What do you do as an event promoter when the crowd you organise gigs for, not to mind your own friends, have all left?

For John Mahon, a former director of Bodytonic and the man behind the revival of the Bernard Shaw venue in Dublin 2, the recession and the mass emigration which followed meant having to work doubly hard to find a whole new audience.

“A lot of my friends were involved in creative industries like architecture, music, design, and they felt the pinch early on,” he says.

“There was one night in the Twisted Pepper which stands out in my mind. I was in the DJ box looking out at the dancefloor, and it felt like there were a load of people missing. I couldn’t put my finger on who exactly, until I started thinking about all the people I had presumed would be there, who used to come to these nights all the time. I thought, he’s gone, and she’s gone. They are all gone. The whole scene I was involved in had hollowed out.”

A lot of his friends were involved in creative industries like architecture, music and design, and had felt the recession pinch early on. While the majority of them left for work abroad, Mahon says many more went because all their friends had gone, and they didn’t want to be left behind.

“I had no interest in leaving, I didn’t have to. Ironically, the Shaw did really well out of leaving parties. At one point, there was at least one person booking a big area for friends to say goodbye every weekend,” says Mahon, who now runs The Locals, a company organising parties, pop-ups, markets and other Dublin events.

“As a promoter, I always have to think about who will be interested in a gig, who will go, who will help me talk about it or get their friends to go. All the people I was relying on were suddenly gone. We had to work a lot harder, and find a new crowd.”

Mahon had been involved in organising the Airbound festival, which originated in Croatia before moving to London in 2010 for a big party on a boat on the Thames every Good Friday. The first year, about 600 people flew over to London from Ireland. As the years went by, the event grew in size but fewer people had to travel from Ireland, because they were all already living in London by then.

“The event became an annual reunion for the Dublin crowd in London. It was a bit special, especially for me as one of the ones who didn’t emigrate,” Mahon says.

“Being over in London with them all and hanging around with them was great. They were all living in different parts of the city and didn’t really see each other, so this was a great excuse for everyone to get together once a year. There was a special resonance: everyone being back together, in another country. In the background was the subtext of emigration.”

Last year, Mahon and Jon Averill of Shock World Service, who lives in London, decided to host the "reunion" at Christmas in Dublin, and came up with the idea for an "emigrant disco". So the Saturday before Christmas, hundreds of people gathered in the Sugar Club after flying in from all around the world. Some arrived straight from the airport with their suitcases in tow.

“It was special seeing all the old crowd together in a Dublin venue, the way it used to be five or six years ago,” Mahon says.

The event was a sell-out success, so they are doing it again this Saturday, this time in Tengu above Yamamori on Ormond Quay. Space Dimension Controller, an international dance music act from Belfast, is the big draw, supported by Dip, playing house and disco. Downstairs, DJs including Mahon will be playing in the bar, and there’s also a space where people can have a chat and catch up.

A smaller satellite event will be held on Tuesday in the South William, a little closer to Christmas for those who can't make it on Saturday, with a story performance by Hugh Cooney, followed by music from "emigrant DJs" who have themselves flown home for Christmas.

“The Emigrant Disco is almost a selfish gig, a big reunion for all my own friends,” Mahon says. “As a promoter it is one of the easier nights to run, because everyone is out on the Saturday before Christmas. The night feels like the way it used to be in 2008. You don’t even have to call or text people, they will just be out, all of a sudden, for just one special night of the year.”

The Emigrant Disco takes place at Tengu this Saturday December 19th. Doors 10.30pm. Online tickets for the Emigrant Disco cost €13.29 and are available at eventbrite.ie . See facebook.com/theemigrantdisco for more information.