When Tony Blair lived in London's labour-held Islington he decided, along with many other parents disgruntled with the quality of the borough's education, to send his children to secondary schools outside the area. In 1999, the Government intervened and Islington LEA became the first to be privatised. Nick Robinson follows the process of change and its impact on schools such as the Catholic secondary St Aloysius, where Tony Blair could have sent his sons. See Choice. (S)