London has one of the largest concentrations of universities and higher education institutions in the world. It has 40 higher education institutions (not counting foreign Universities with London branches) and has a student population of more than 400,000. Among the institutions in London are some of the old colleges that today make up the federal University of London, modern universities, as well as a number of smaller and often highly specialised universities and colleges. Additionally, over 45,000 students in over 180 countries follow the University of London External System, established in 1858. Major universities Major universities are considered to be those included as universities in at least two of the three national rankings of universities. Key (lower numbers are better): GUG: Guardian University Guide 2018 (published 2017) TUG: Times and Sunday Times Good University Guide 2018 (published 2017) CUG: Complete University Guide 2018 (published 2017) UoL: Part of the University of London QS: ranking in QS World University Rankings 2018 THE: ranking in Times Higher Education World University Rankings 2017/2018 RG: Russell Group, a self-selected association of 24 large British public research universities ARWU: ranking in Academic Ranking of World Universities 2017 Notes: a Imperial College London, was a college of the University of London but left in 2007. Branches of UK Universities in London Anglia Ruskin University Coventry University London and CU London Glasgow Caledonian University London Loughborough University London Newcastle University London Northumbria University London Staffordshire University London Sunderland University London Teesside University London Warwick Business School London Ulster University London Campus University of the West of Scotland London York St John University London Campus Specialised and private universities and higher education colleges The following institutions offer British undergraduate and postgraduate courses, but are usually specialised in one or two academic fields. Colleges which form the federal University of London are in italics. Academy of Live and Recorded Arts (Drama) - Wandsworth Architectural Association School of Architecture Bird College (Dance) - Sidcup BPP University (Business, Law, Healthcare) - Holborn/Waterloo/Shepherd's Bush/City of London British College of Osteopathic Medicine (Medicine) - Finchley Road British School of Osteopathy (Medicine) - Newington Royal Central School of Speech and Drama (Drama) - Swiss Cottage City of London College - Whitechapel Conservatoire for Dance and Drama (Circus/Dance/Drama) - made up of a range of institutions, those in London are: Central School of Ballet - Clerkenwell London Academy of Music and Dramatic Art - Barons