A small group of British physicists, working a mile underground in a north England potash mine, are taking on the world's biggest and most expensive particle accelerator in a race to find the universes most elusive substance. Working with a tiny budget, the team of British researchers have built a machine in a mine tunnel which they hope will enable them to detect dark matter - the substance thought to make up 95% of the mass in the universe. It pits them against Cern, a multi-billion-pound project in Switzerland.