This note describes the UK’s current and future involvement in large science facilities on which it spends £230 million of public funds each year. It describes key facilities already constructed, including the Large Hadron Collider at CERN in Geneva, which will start taking data later this year. It also looks at a several large facilities already in planning, including the £1 billion EU “spallation source” for nuclear research, for which the UK is a key contender to host, along with Sweden. The note looks at the scientific rationale behind each facility as well as policy issues arising such as legal ownership and benefits to the UK, and the recent controversy over UK funding for big science research.