I wrote the script over the next year with some companies showing interest in producing it. It originally started life as "The Last Tube" but I re-wrote it at the pitch stage to remove the reliance on London Underground.

Although a fully fledged, big-budget disaster movie, I've always felt that the script can be scaled to any size. It's a broad canvas but I can easily see a low budget crew pulling it off by focusing away from the mega-structure and more on the intimate action. In fact it would add to the claustrophobia of the world.

Moving in the other direction you could blow it up big and aim for a TV series. Here's a contained city underground because life on the surface is too risky for whatever reason – terrorism, natural disaster, chemical warfare – you name it. Life there has all the challenges society has now along with some new ones and lots of opportunity to explore character stories, all in a confined space. Think Star Trek on earth!

So read on to get a glimpse of this new world as people fight for their lives in the battle to survive in Subterrania.