As part of its work, the European Concerted Action ''Tissue Characterisation by MRS and MRI'' (COMAC-BME) has expended considerable effort in the field of magnetic resonance imaging (MRI) quality control. A set of test objects - the Eurospin set - have been designed and rigorously tested in many systems throughout Europe. The full history of this development is described, together with a detailed presentation of the types of measurements that are achievable with such test objects and examples of the results. Further, the principles of more complex Stage II tests (which involve invasive interaction with the system) are introduced. Finally, simplified methods of quantifying the overall performance are discussed and the levels of MRI quality control from acceptance testing to routine quality assurance outlined.