in britain, scientists also considered whether an atomic bomb was practical. at the university of liverpool, chadwick and the polish refugee scientist joseph rotblat tackled the problem, but their calculations were inconclusive. at cambridge, nobel prize in physics laureates george paget thomson and william lawrence bragg wanted the government to take urgent action to acquire uranium ore to keep it out of german hands. the secretary of the committee for imperial defence, major general hastings ismay asked sir henry tizard for an opinion. tizard was sceptical of the likelihood of an atomic bomb being developed, reckoning the odds of success at 100,000 to 1.