This month the New End theatre in Hampstead, north London, is conducting an ambitious experiment. For the duration of the four-week run of Where's Your Mama Gone?, every ticket will be sold on a "pay what you can" basis.

"Pay what you can" is not a new scheme. A handful of London fringe venues have been doing it for years, the nitty-gritty varying from theatre to theatre. At the Tricycle in Kilburn, the offer applies to performances on Tuesday evenings and Saturday matinees, it's only available to concessions, and it's only possible to buy these tickets in person on the day of the performance. Riverside Studios lets anyone turn up and pay what they want for tickets, but only run the scheme on first previews of some productions. The PWYC programme at east London's Arcola is also open to everyone, runs on Tuesday evenings only and is first-come, first-served on the night. There are, of course, many others.

The New End has never run a scheme of this kind before, but that hasn't stopped the theatre from jumping straight in with the most open "pay what you can" offer around. Not only is every ticket for every performance of the run "pay what you can" (the recommended price is £15), but these tickets are also bookable in advance and available to anyone, regardless of their circumstances.

The aim of the experiment is to open up the theatre to new, more diverse audiences, but low ticket prices alone won't be enough. If the New End is to attract theatregoers from beyond its regular pool of privileged locals (Hampstead, where the theatre is located, is one of the most well-to-do areas in London), much depends on marketing. This is something that the team is addressing, at least as far as the current run goes: Where's Your Mama Gone? tells the story of two children put into care after their mother is murdered, so the New End is focusing its attention on working with a number of children's charities, colleges and universities to spread the word about the show and the offer. If the theatre decides to pursue the scheme long-term, of course, a great deal of work would need to be done to make sure that the sort of people the theatre is hoping to attract are made aware of what's available. Not every show will be so easily marketable to a special interest group.

There is a paradox, though. If the scheme succeeds in bringing in new audiences paying less than the recommended ticket price that has obvious implications for the box office. Brian Daniels, artistic director at the New End for the last 14 years, and writer of Where's Your Mama Gone?, says that the theatre has budgeted for the show on the assumption that very little will be taken at the box office, but that this has only been possible because the actors have agreed to work for half of Equity minimum and the director is doing the show for nothing.

It may be socially laudable, but it's hardly a viable business model. But then again, can we say that about any fringe theatre? Actors, creatives and administrators working on the fringe are paid appallingly – if they are paid at all – even when theatres produce hits. I'm not defending exploitation, but since the current system falls short when considered in these terms, perhaps the New End's experiment is worth a try. If the theatre can widen the diversity of its audiences, and by doing so up its ante as a cultural space of real value, then perhaps that's enough. We'll have to wait and see.