Colleges within universities in the United Kingdom can be divided into two broad categories: those in federal universities such as the University of London, which are primarily teaching institutions joined in a federation, and residential colleges in universities following (to a greater or lesser extent) the traditional collegiate pattern of Oxford and Cambridge, which may have academic responsibilities but are primarily residential and social. The legal status of colleges varies widely, both with regard to their corporate status and their status as educational bodies. London colleges are all considered 'recognised bodies' with the power to confer University of London degrees and, in many cases, their own degrees. Colleges of Oxford, Cambridge, Durham and the University of the Highlands and Islands (UHI) are 'listed bodies', as "bodies that appear to the Secretary of State to be constituent colleges, schools, halls or other institutions of a university". Colleges of the plate glass universities of Kent, Lancaster and York, along with those of the University of Roehampton and the University of the Arts London do not have this legal recognition. Colleges of Oxford (with three exceptions), Cambridge, London, and UHI, and the "recognised colleges" and "licensed halls" of Durham, are separate corporations, while the colleges of other universities, the "maintained colleges" of Durham, and the "societies of the university" at Oxford are parts of their parent universities and do not have independent corporate existence.