It was a hot night in the BT, and the small but international audience were poised on the brink of a new sort of theatre experience. Uncertain what we had signed up to, we were about to get to know each other's values and ideas much more thoroughly than most audiences.

The Lab Collective have put together a timely and worrying show, exploring issues around immigration. How do we weigh up the needs and wishes of migrants applying to come here? What will they offer us, and what will they need from us? Who is doing whom a favour? And what kind of migrants do we find most appealing?

The setup is quite straight forward: The Lab Collective's research is meticulous, and the background they present on each prospective immigrant is based on real-life scenarios. Two immaculate and aggressively cheery presenters (played by Matthew Flacks and Amelia Vernede) explain the situation - in a Hunger Games-esque future a number of shire states form a Southern Alliance, each taking a quota of new migrants. The audience are divided into regions, and each elects a councillor to the board. Only councillors can vote, but everyone can have their say (as volubly as they like!).

And then we are let loose. The crowd was a little spread out, and initially a bit quiet. The presenters intervened, encouraged, and hastened us, but the amazing experience really lay in the debate. The audience/council/electorate argued and debated. How far you comply with the rules is up to the makeup of your group. And of course the points you should have debated will keep occurring to you for several days after the event.

This is the first time the show has been performed outside London, but of course these questions are applicable everywhere. The Lab Collective are visiting festivals this summer, and are hoping to arrange a tour of the north of England. I'm sure there's a PhD in the various audience reactions, and I'd love to see this delivered as a citizenship lesson in all secondary schools, if only to demonstrate the importance of being one of those with power, or at least being represented in the democratic process.

I was anticipating proceedings might be a bit worthy and grim. I was wrong. While uncomfortable in parts, it was fascinating to properly understand others' perspectives, and eye-opening to see your own prejudices. The premise might have been simple, but the debate continued in the corridor and right into the street outside.