Established at a conference held at the Clarendon Street School, Nottingham on 27 March 1897, as the National Federation of Head Teachers' Associations, the National Association of Head Teachers or NAHT is the British Trades Union for the head teachers of British primary and secondary schools in the state sector. (Head teachers in Private education have their own Headmasters' and Headmistresses' Conference.)
Despite it name, its membership is not restricted to the head teachers of schools; both deputy headteachers (since 1985) and assistant headteachers (since 2000) are also allowed to join. It has a membership of over 30,000 and claims to be the largest organisation of its kind in Europe.