This paper describes the storage of the 12 million items that have just been moved into the new British Library building. The specifications for the storage and environmental conditions for different types of library and archive material are explained. The varying environmental parameters for storage areas and public areas, including reading rooms and exhibition galleries, are described. An early assessment of the physical conditions in the new library building is made, reviewing the achievability of the specifications in practice, together with an appraisal of the overall effect of the improvements to the macroenvironment on the collections. In the second part, the microenvironments of enclosures used at the British Library are described. Comparisons of costs and the amount of practical protection afforded by different types of enclosures, from drop-back boxes to chit-su-type boxes to phase boxes, is made. The paper describes exemplar boxing projects in preparation for moving large quantities of material to a new building and projects to test an environmental specification using dataloggers within enclosures. It concludes with current work examining the possible use of vacuum packing and oxygen-free storage of, particularly, newspapers. (Author/MES)